There's pretty much two reasons why you might be reviewing this guide, or maybe a combination of both:

1. You're here to nod your head in approval because you love the Engi (who doesn't?), OR:
   
2. You want to learn How to Kick @$$ as Engineer. Bonus points to the author of this guide for the sleek title drop.

Well, I have some good news for you. You've come to the right place.

In this guide, I will discuss the following:

• The Power of Command: First and foremost, the number 1 prerequisite you should take to making your Risk of Rain 2 runs much easier (if you haven't done this already).
  
• Intro to Item Priority Basics: A concise mini-guide on how to frame builds in a metagame context, particularly in games where you team up with other people. Just something really useful to keep in the back of your head at all times. Realistically, this will help with builds across ALL survivors, not just the Engi. However, for the purposes of this guide, the few given examples will be all about you-know-who.
  
• The Tank Loadout: Split into two parts due to character constraints. A classic Engi build, viable practically since the launch of RoR2. It quickly becomes more potent the more you diversify with items - but there is one item that you will definitely be stacking. A lot. Yes, that item.
  
• The Mobile Bruiser Loadout: A newer Engi build, primarily focused around mobile turrets, spider mines, and thermal harpoons. I will recommend what I think is the best way to do this, but you of course can mix and match to add some flexibility in your build.
  
• Conclusion: Final rundown on the major points of this guide from a metagaming standpoint, once you're confident you've thoroughly digested the main material.

This guide assumes the following:

• You have played a video game (or video games) before and understand what a video game is, and can frame the context of video games separately from the context of reality. I can only hope that this is true for you.
  
• You have a basic idea of what "metagaming" is and what it means (in the context of video games and not pencil and paper RPG's). In short, "the game outside of the game" - or more specifically, in this case - strategy guides like this, intended to help people maximize their gameplay methods. Much of this is also known as "theorycrafting". Some people think metagaming is cheating in this context. Those people are all objectively wrong. A much better example of "cheating" would be using a popular memory editor to modify the number of lunar coins in your game to an absurdly high amount so you don't have to worry about them anymore, because you got tired of farming them and care more about experimenting and having fun with the game than waiting until the developers will make them just a little bit more accessible. I have definitely not done this myself and in no way am I advocating for anyone else to do it. It's cheating. What kind of jerk would do that?
  
• You have played Risk of Rain 2 at least a handful of times, and have a basic familiarity with the general mechanics. On top of this, you want to play as Engi and know the best items to get.
  
• You have played enough RoR2 games with your friends (or strangers, god help you) to understand how multiplayer can change the course and outcome of your runs.
  
• You know the significance of RoR2's items and how they dynamically affect gameplay - you may or may not have unlocked a fair bit of them already, and in general you are familiar with how the loot system works.
  
• You may not be entirely familiar with what each and every item's exact effect is and/or how it stacks, but you are willing to follow this link to the Items page on the official RoR2 wiki to find out[riskofrain2.gamepedia.com] as you're reading this guide. Why? It would be entirely pointless for me to maintain exactly what each and every item is and does in a guide that will get updated less frequently than the wiki itself, which has better up-to-date information anyway. The wiki is where you should be looking if you have general questions about the game or how to unlock stuff. To that end, take everything I say in this guide with a grain of salt knowing that some items get buffed/nerfed over the course of balance updates, and this guide may not be entirely accurate as time marches on. However, it will at least give you a general idea of what items you will need to build Engi with.

So, without further ado...

Recently as of the creation of this guide, one of the latest content updates has been pushed out by the glorious developers. This new update contains something called Artifacts, which can be enabled at the start of your run. If you're familiar with RoR1, all of the artifacts from the original game have returned... and you might see already where I'm going with this.

Most artifacts will only make your life hell for the extra challenge and bragging rights, if you can go deep enough on a run with them. However, we won't be talking about those ones. In particular, there is one artifact that will entirely remove the RNG rolls for items within their own rarity pools - allowing you to pick exactly which items you want. This works wonders for experimenting with builds and is pretty awesome in co-op.

I'm talking about the Artifact of Command.

So how do you get this artifact? For that particular inquiry, I would defer you to the Artifacts page on the official RoR2 wiki.[riskofrain2.gamepedia.com] Again, the artifact you want is Command, and that page will show you how to acquire it. I suppose some would consider using the wiki in such an atmospheric game to be a spoiler, but this guide assumes you're acting in pragmatism and don't mind "cheating" to know the code for unlocking the artifact(s).

Once you've unlocked Command, you can set your sights on enabling it for future runs.

Fair warning, this part of the guide may be a bit boring... but it is critical to understanding how to maximize your efficiency and maintain parity in Risk of Rain 2, and it applies to more than just Engi. I'll try to cut the minutia and give you meat and potatoes here.

In total, there are 4 basic ways to classify item drops, in ANY build. This is ESPECIALLY important when you're playing co-op with people who are probably not going the same class as you. Honestly, IMO this is a better way to think about items than ranking them in the comparatively abstract "tier list" meme, if only because you want to craft your build specifically to suit your own needs and gameplay taste, and tier lists rarely do that justice.

This classification system determines priority over particular items, in descending order:

1. Essential items: First and foremost. These are items that your build/class REQUIRES in order to be effective in survival, combat, mobility, and utility to effectively contribute to the rest of your team. Engi has quite a few essential items, and luckily, few to none overlap with that of other classes. If an item is essential for the build you plan on, make sure you discuss this with your team beforehand and agree that you MUST have priority over these. In builds where essential items overlap, agree to negotiate who gets what when, or at the very least least split items evenly or consider picking a build to complement your teammates.
   
2. Useful items: These are items that can (and will) help you with your build but generally are not required. They are nice to have for you, but they may be essential for others! Always, always, ALWAYS yield useful items to others on your team if they see it as essential. Don't be greedy!
   
3. "Situational" items: These are items that are largely pointless and have limited or no functionality with your build. Don't bother picking these up unless absolutely nobody else needs them or wants them. If it's an arguably useful item (like Lens Maker's Glasses), allow everyone else on your team to stack them up to comfortable levels first. Also consider it's not a bad idea to stack all of the pointless items on one person, so that if you find a 3D printer with a good item in it, they can throw the game for their teammates without risk of other people destroying their builds. Ironically though, Engi is not a bad class to do this with - especially in runs where you're hunting for a Fungus printer.
   
4. Detrimental items: These are items that you should generally avoid picking up, or just items that are garbage tier in general (Warbanner, Rusted Key, Medkit, etc.), unless you really want that dank logbook entry. More often than not, this will be a lunar-rarity item. However, there is one good lunar item that is AMAZING on Engi - Visions of Heresy. If anyone else on your team finds this and they're not playing Engi, ask them to yield it!

Always consider this hierarchy of item tiers, both for yourself and other players. If you want your game to have any sort of structure to it, be sure to plan this out before rolling out with a team! It will make your life so much easier!

Most important of all though: be reasonable. Risk of Rain 2 has no innate anti-loot-ninja features. If you have a tendency to steal loot, just don't be that guy. But why, you might ask? Well, being a loot ninja just sucks the fun out of the game for other people. However, this is in addition to another, perhaps less-obvious reason: this will eventually ruin your fun in the end too since you incited rage against yourself from other people (rightfully so), and suddenly nobody wants to play with you anymore. The run will have more longevity and breed more camaraderie if you can agree to be as fair and as utilitarian as possible in your loot distribution, and that's honestly the best way to play RoR2 - the fun way. Being a loot ninja doesn't pay.

Alright. So here's the Engi build we all know and love. Bustling Fungus. Amirite? But wait, there's more! As Engi, your primary goal in a team game is to be a tank/support character. Fungus is the bare minimum essential item, but there are a few more to consider besides that for working out essentials.

For this build, on the Loadout screen, go with all of Engi's default abilities, except the mines (so take bubble shield and stationary turrets). It's up to you to choose which mines to use for the run, as it boils down more to personal playstyle. Do you actually care about strategically placing your mines and giving them ample time to arm, to maximize their damage? Or would you rather just spam them everywhere? I tend to lean more towards spamming, so I prefer the spider mines. The latter strat tends to have higher DPS in target-rich environments, however, so it's useful late-game.

Now, for the item list, in order of utility (compared to other classes).

Essential items:

• Bustling Fungus (Common) - In general, just stack as many of these together as you possibly can. This is Engi's bread and butter item. Comparatively, they are almost entirely useless on any other class, so unless you're playing with overly greedy morons (why would you?) just snatch them up as soon as you see one. If there are two Engis in the same run, be sure you are splitting them equally. Alternatively, if one of you has the requisite challenges complete, one Engi can always go the mobile bruiser build (listed below).
  
• N'kuhana's Opinion (Legendary) - The first one of these is always yours. No exceptions. Eventually, once you stack enough fungus while carrying this item, your turrets will just slay anything that comes near them. The more you stack these, the more powerful you and your turrets get. You may consider allowing other players in your party to pick them up for the benefits they give, especially since they will be frequently in and out of the healing radius of your turrets.
  
• Aegis (Legendary) - The amount of overshields this item gives you with your build will be pretty ridiculously good, especially on your turrets, which it will be constantly applied to. It's hard to justify letting another player have it before you take your first one, unless they're able to consistently heal themselves with attacks and are otherwise pretty squishy (such as Artificer or Huntress). Again, consider distributing duplicates among the team (like with N'kuhana's).
  
• Rejuvenation Rack (Legendary) - This essentially gives you double healing powers. That means you will spit out higher DPS from N'kuhana's Opinion, in addition to double overshields with Aegis, and much, much faster healing for any party members walking into your heal range on your turrets. Again it's hard to justify giving this one up, so it's essential. Eventually each one of your party members will want one though (just like all the red items).
  
• Dio's Best Friend (Legendary) - Although just about anyone on your team will want at least one charge of this with them at all times, it is best utilized on Engi, because it allows his turrets to revive themselves. How many charges you stack will determine how many charges each (new) turret you place gets. Dio's is user-independent, meaning whoever dies will burn a charge of it on themselves only. To give you an example of this: Let's say you're Engi (likely the whole reason you're reading this guide, har-har). You pick up one Dio's. That Dio's will always be on you. Every (new) turret you place will spawn with one Dio's. If that new turret you placed dies, it will revive once and burn its own Dio's without touching yours. You can still continue to place new turrets and they will inherit the Dio's you still have, getting one each. However, if you die as Engi, you will burn your own Dio's and revive. From that moment forward, none of the turrets you place will spawn with a Dio's (unless you stack more). Generally speaking it's good to stack these late game, though that goes for anyone else on your team.
  
• Bandolier (Uncommon) - Hands down, this is an Engi item since your turrets are the skill with the longest cooldown, and you must have them up at all times. This will also refresh one mine per pickup, so it is useful if you have lots of backup magazines. You could justify yielding this to an Artificer or Mercenary on your team, though. Talk it out!
  
• Visions of Heresy (Lunar) - This is 100% an Engi item. First of all, it replaces your grenades with an actually reliable direct upgrade: Homing sticky grenade projectiles. On top of that, this also applies to your turrets' basic attack, so they will start shredding through enemies that they target. It deals a TON of DPS, so there is absolutely no reason not to pick it up. Just do it. You won't regret it, I promise!
  
• Interstellar Desk Plant (Legendary) - While not essential by any means, this definitely makes the most sense on Engi with this build. Your team will benefit more from this if you grab it and stack it than if someone else grabs it.

Useful Items:

• Paul's Goat Hoof and Energy Drink (Common) - Engi has the worst mobility out of any character in the game. This will help him literally get up to speed with everyone else. Artificer has the second-worst mobility, so yield some to the Artificer(s) in your party and don't forget to share/split whenever possible.
  
• AP Rounds, Backup Magazine, Crowbar, Gasoline, Personal Shield Generator, Soldier's Syringe, Stun Grenade, Topaz Brooch, Tougher Times, Tri-Tip Dagger (Common) - All are these are useful for you, but almost all of them can be better utilized on other classes. For instance, Crowbar, Gasoline, and Dagger will help increase your overall damage, which is great but not necessarily your priority. Soldier's Syringe will increase your overall DPS and let you put mines out faster, but it is again better utilized on other classes. Picking up enough items that give debuffs will be great for Death Mark if you plan on incorporating that into your build.
  
• Hopoo Feather, Red Whip, and Wax Quail (Uncommon) - Again with the mobility argument, Engi is the the worst. Pick up a few of these as soon as you can. Make sure the rest of your team is comfortable with mobility first though. After all, more mobility does nothing to benefit your (stationary) turrets in any way!
  
• AtG Missle Mk. 1, Berzerker's Pauldron, Chronobauble, Death Mark, Kjaro's Band, Old Guillotine, Old War Stealthkit, Razorwire, Runald's Band, Ukulele, and Will-o'-the-wisp (Uncommon) - These are all great items for Engineer, as it gives you and your turrets reliable crowd control, survival and damage capabilities. However, it's not essential for you, so yield these to any other class who could conceivably benefit more from them. Everyone should pick up at least one of each of these at some point, so before anyone starts stacking them, make sure everyone has one.
  
• Genesis Loop and Titanic Knurl (Boss) - Fantastic items for your turrets, since they will be pulling the enemy's aggro and taking damage constantly. Both of these will help, but Genesis Loop is arguably better since it's a scaling bonus rather than a flat one. Also the knurl is better utilized on squishier classes that need it more than you do.
  
• Frost Relic, Sentient Meat Hook, and Unstable Tesla Coil (Legendary) - All three of these are pretty awesome on your turrets, but they're even more awesome on melee classes. If you have a Mercenary, Loader, Acrid, or MUL-T (with the buzz saw) in your party, always yield these to them first.
  
• 57 Leaf Clover, Alien Head, Brainstalks, Brilliant Behemoth, Ceremonial Dagger, Happiest Mask, Resonance Disc, Shattering Justice, and Wake of Vultures (Legendary) - None of these are bad choices for you, but again, these items are simply better utilized on other classes.

The granularity here is not my problem. Wish these two parts were all one big thing? Me too. Thanks, Steam.

"Situational" Items:

• Squid Polyp (Uncommon) - This one is much like Interstellar Desk Plant, in that it's marginally useful for anyone who grabs it, but slightly better on Engi. This is because they are timed life and will eventually die off without being healed, which is where your Fungus comes in - you can always place your own turrets near them to keep them alive. It's a good item for you, but you should focus on items that are higher in this list.
  
• Bundle of Fireworks, Cautious Slug, Fresh Meat, and Sticky Bomb (Common) - These items are alright, but they don't give you or your turrets much utility. Bundle of Fireworks and Sticky Bomb are free damage and procs, so yield those to someone who is going for a build that depends on procs. Otherwise grab them. Yield Cautious Slug and Fresh Meat to melee classes since it's much more important for them to take these for their own survivability.
  
• Lens Maker's Glasses (Common) - Always stack these to 10 and then forget about them. What makes them "situational" in this case is that you don't necessarily NEED them as Engi. Be sure other builds that rely more on dealing damage and less on tanking it stack theirs up first so that they can dish it out better.
  
• Focus Crystal (Common) - Mostly useless on Engi. There's a case to be made that they benefit your turrets, but that really is debatable, especially since they're much better utilized on any melee class. Only pick these up if nobody else wants them.
  
• Fuel Cell, Ghor's Tome, Harvester's Scythe, Infusion, Leeching Seed, Predatory Instincts, and Rose Buckler (Uncommon) - None of these are particularly useful for Engi under normal circumstances. Infusion is nearly useless on your turrets unless they are able to kill dozens of enemies per second each, because every time you redeploy a turret, they lose all of their Infusion stacks. Yield this to a player who needs more HP than you do, especially if they have Transcendence or Shaped Glass (it will synergize fine with either of those items since both are based on health percentages). In addition, Fuel Cell isn't great unless you can fully utilize it with a good item in your equipment slot and/or pair it with Gesture of the Drowned.
  
• H3AD-5T v2, Hardlight Afterburner, Soulbound Catalyst (Legendary) - Headset and Afterburner are entirely useless to Engi. Yield those to classes like Mercenary, Huntress, MUL-T, Commando, Acrid, or... pretty much anyone who isn't Engineer. As for the Catalyst, what makes this kinda bad on Engi is that your turret kills do not trigger its effect, and your turrets will be doing most of the killing late game (if you're building Engi right).
  
• Beads of Fealty (Lunar) - A lunar item with no drawback. Grab this if you want more lunar coins when you obliterate. If you don't care about that, you can at least stack a bunch of them up and toss them into a cleansing pool for pearls, if that's what you want to do. Just be mindful of any other lunar items you might have stacked up when doing so.
  
• Gesture of the Drowned (Lunar) - Realistically, this item is only as useful as your Equipment item is. It's certainly not bad, but it's not important unless you want to constantly be using Foreign Fruit, which is arguably good on this build, or another defensive item like the Jade Elephant. Alternatively, GotD pairs pretty well with Radar Scanner if you keep forgetting to hit Q to scan the map for everyone (my personal favorite item synergy).
  
• Focused Convergence (Lunar) - Good for speedruns. Your turrets will gain them when you place them, meaning you can charge the teleporter pretty quickly even with just one. It's mostly up to you if you want to snag one for yourself, but be sure to talk it out with your team first and make sure they're on board with your plan.
  
• Helfire Tincture (Lunar, Equipment) - Personally, I think this is a great item despite its drawbacks and reputation, especially since your mad heals will be counteracting its negative effect. The damage is well worth it in my opinion, especially on Engi. Problem is, other people tend to complain about it when you use it... just have some situational awareness and you'll all be fine. If anything you can justify using it with your team since you'll be the one doing most of the healing anyway.
  
• Effigy of Grief (Lunar, Equipment) - The real question is why you would even want this. That was a long-standing question for me, too until - as it turns out - it has a beneficial utility with the Command artifact turned on. Using some cheese strats, it's possible to pick the item up, use it (creating the pillar), grab any Equipment item into your inventory, and then pick up the Effigy pillar. Your orange Equipment item will drop as a command and you can pick a different Equipment item, leaving the Effigy behind.

Detrimental Items:

• Medkit, Monster Tooth, Repulsion Armor Plate, Rusted Key, and Warbanner (Common) - While not necessarily "detrimental", these are really rather useless mid- to late-game due to the marginal linear bonuses they give you. If you're playing Engi, stack these up for your team so that you can give yourself a bunch of Fungus if you find the right 3D Printer.
  
• Brittle Crown, Corpsebloom, Shaped Glass, Transcendence (Lunar) - Brittle Crown should never really be considered unless you have Sacrifice turned on, and even then it's a garbage-tier item, even for being Lunar. Corpsebloom, Shaped Glass, and Transcendence will have a negative effect on all of your healing abilities, which can ruin your build and maybe your entire run. Just don't pick any of these up unless you absolutely know what the implications are, and you're OK with the potential consequences. Still, Shaped Glass and Transcendence are so much better on other classes than Engi that it's best to just yield them to your teammates anyway.
  
• Spinel Tonic (Lunar, Equipment) - The downside of this item just makes it not worth the trouble in any way. Theoretically, if you got enough Fuel Cells and/or Gestures of the Drowned, sure, you could keep it active permanently. Remember though that it has no effect on your turrets, just you. Personally, I'd rather get Uncommon items that are more useful for my overall build, and stack Visions of Heresy instead of GotD's. Just let one of the yahoos on your team punish themselves with this item if they really want it.
  
• Glowing Meteorite (Lunar, Equipment) - If you're doing a single player run and you think you can out-tank it, go for it. However, if you're playing multiplayer, just... just don't be that guy. Seriously.

DISCLAIMER: As I'm not entirely done experimenting with this build, this part of the guide is a work-in-progress. I'm still trying to find viable strategies. Please give me a heads up if you come up with any ideas in the comments and I'll make a note of them here.

What I call "The Mobile Bruiser Loadout" is essentially a pet build involving the mobile variant of your turrets, thermal harpoons, and spider mines. Needless to say, Fungus will no longer be viable in this build, and mobility is in big focus since it is key to your survival and ability to deal damage. Essentially, build Engi like you would any ranged class with low starting mobility, particularly the Artificer. So far I've seen it's hard to go wrong when you do it that way.

If you're not entirely comfortable with this, just do the tank build. If you follow my instructions you'll be a force to be reckoned with on that front.

By now you should have a firm grasp of how to be more effective in building out the Engi.

In summary:

1. Follow the item guide in future runs. You will find that your builds will be much more successful if you unlock and enable the Artifact of Command. The same goes for the Artifact of Sacrifice, if you would rather use that to cheese locations that have few to no chests and stopped timers, like any of the hidden realms. These two artifacts combined will assist greatly in performing other unlocks as well as it removes much of the obstructive RNG.
   
2. Be fair with item distribution and maintain situational awareness. Engi is as much of a tank as he is a support class. Your teammates rely on your cooperation and assistance to progress through incredibly deep and challenging runs, just as you rely on them to do the same. This is especially true in Monsoon runs. The payoff to this is intrinsically rewarding, especially if you can help your friends achieve unlocks.
   
3. Just have fun. This is a video game, after all!

Thanks for taking the time to read this far. This guide was quite exhausting to write as it's my most comprehensive Steam Community guide to date. That being said, all feedback is welcome in the hopes of me improving my skills updating this guide, as well as writing more guides in the future. I can't promise delivering on any requests, but I will try!

Game On,
KoblerMan