Starting with what I'd rate this, maybe 3/10. There isn't a whole lot that really seems to be praiseworthy here between the gameplay, plot, characters/character development. I'll try to break it down as best I can while being as objective as I can about it. I'm going to put this here since while I think maybe this belongs in plot I am unsure, when the Master that you get to name at the start talks or thinks, a full screen square box comes up. I say talks or thinks because a fair amount of time it is not apparent whether they are thinking or talking and you have to figure it out when the character they are conversing with next talks, I have no idea why they did this and it annoys me greatly. This was present in Fate/Extra as well and it was terrible there too. Oh and when I say it isn't apparent whether they are talking or thinking I mean the way the dialogue may be written will sometimes directly say something towards whoever the MC/FMC is talking to and sometimes it will be written indirectly as if they are thinking; not actual example but such as "Hmm Saber seems worried" then Saber will respond as if the MC/FMC said "Saber you look worried."

Gameplay: In-stage you are taking out hordes of enemies that cause "aggressors" or zone damage sponge enemies to spawn that you beat in order to claim the zone, lather rinse repeat until you have enough to cause the stage boss, some servant based on each stage, to appear. You beat them and you win the stage. Before, during, and after stages, while playing the main story at least, there will be plot scenes that occur giving some insight as to why you are there and why you're fighting, sort of. After a couple stages you are able to do "side quests" during stages to raise bond levels with various servants, these side quests are what you would normally do beat enemies, do certain attacks, pick up recovery items. and so on. Bond levels grant slots for that specific servant to equip "install skills" that grant various stats such as, attack, defense, poison/fire/ice/lighting to attacks, damage per KOs, etc. These install skills are primarily obtained from beating the aggressors I mentioned at the start of this paragraph. The actual combat is very much button mashing with maybe throwing in some heavy attacks to stagger/stunlock enemies that you aren't able to do that to with the light attacks you will be spamming. The camera seems to be fighting you on focusing on aggressors and doesn't keep focused on the bosses, the only ones you can lock on to, while you are actively comboing. Majority of the gameplay doesn't feel very rewarding especially with the following parts that are a bit of a chore, in my opinion, to go through. There is also equipment that the MC/FMC can put on that can do some things that I guess is supposed to be a semi-holdover from Fate/Extra and while some of it is actually a good idea I didn't care for it much. It is serviceable enough but not really impressive maybe a 3-3.5/10

Plot: So upfront I feel this is just bad and I'm not sure if this would be better or worse to other people if you have played/watched Fate/Extra. Avoiding spoilers, when starting the game it is a lot to take in with few answers, which is something I personally hate in storytelling because it doesn't immerse me, it just confuses and annoys me. However, basically you have some arbitrary reason to go through stages to claim/conquer them but everything sort of proceeds at a breakneck pace plotwise. Things fall apart for your "faction" quickly and come together just as quickly, the main story is separated into a few factions with a few stages each and following their side of the story, or I would presume I haven't but likely will complete at least a bit more of the game since I have that compulsion to complete what I started so I usually at least go until pretty extreme burnout then stop playing the game forever. As an aside, after starting the game and getting less than 30 minutes into the game I decided to watch a playthrough of Fate/Extra to see if it helped things, it made things worse for me. This is a review of Fate/Extella so I won't go into my feelings about everything in Fate/Extra however, unless Fate/Extra CCC or Fate/Extra Fox Tails links up a bit better, this games plot mostly deviates dramatically from Fate/Extra. With that in mind, while you would get a more in depth insight into this general reality and how it is different from main Fate/Stay Night timeline and I would recommend it for that reason(Fate/Extra that is), I personally was more frustrated with the plot deviation this game took from Fate/Extra. Oh also the game starts out with you having amnesia, awful start, easily one of the worst plot devices that is hardly ever used in a effective fashion, side note Fate/Extra also uses amnesia but it does it significantly better. From what I've seen 1/10, why am I here, make me want to be here.

Characters/Character development: The characters interpersonal relationships seem to already be established, but both you and Saber are quite different from how you were in Fate/Extra, which plot somewhat explains-ish why you are different. Quite frankly, I don't care for Saber's personality in this game, aside from it deviating from the previous game, it also just feels forced. So far, I haven't really seen characters developing in any meaningful way or getting any form of depth or becoming more than they are from the start, though this might(read doubtfully will) change. The bond system mentioned in the gameplay paragraph adds some interactions here but for me they fall flat since the characters already have their established relationship and this doesn't really give them depth so much as just maybe have some check-in the box fan-service/standard japanese storytelling things. Maybe 1-1.5/10.

Some last tidbits, graphics are fine, pretty good even, not groundbreaking but not bad. The game isn't visually stunning and I was looking more at the minimap to get to different zones to protect or claim them rather than the areas themselves but even still they weren't so spectacular I felt I was missing out on anything. Voice-acting is fine with some of the translation being slightly off from what the characters actually say but well within acceptable range and not remotely egregious. Personally I feel this is generally a really bad game, the primary things I look for in a game, hint hint the things that have their own paragraphs, are all lacking or borderline nonexistent here. I do not recommend the game.

So far I'm 13 hours in and I have completed the first story for Nero and I'm loving it! I've been a fan of Fate since 2018 when I got into it after watching Unlimited Blade Works and I've been hooked ever since.

If you are a fan of Fate this is a GREAT game with a compelling narrative, although the fighting and combos are limited compared to other musou titles it does its job. Fate/Extella Link improves the combat, but the story isn't to the same caliber.

I recommend playing Fate/Extra and Fate/CCC which will give you much needed context from the previous games in the timeline. (Although you don't necessarily need to, it definitely will let you appreciate it more although Extella Umbral Star does explain what happened in the previous games briefly.)