This guide will quickly go over all of the achievements and how to get them most efficiently

Quick summary:
First of all you have to complete the game twice. this is because after fighting a girl will you unlock something called "One hand mode" that is only unlocked after defeating the specified girl once. this means you have to complete every girl twice, once normal and a second time with one hand mode. It's also important to remember to "strip" and remove all clothes once per girl. all other achievements are straight forward

Further explanation further down in the guide.

Some small tips to help you get through the game as fast as possible.
- Difficulty doesn't mean anything for the achievements so just play on the easiest difficulty unless you wanna take on the challenge of the other difficulties. but it's deffinetily more easy with mouse than arrow keys.
- I'm pretty sure bonus stages doesn't really matter. It might unlock characters but not sure.

These achievements will unlock as you play through the game, unlock girls and so on. There's no need to think about these.

There is an achievement to every girl that requires you to remove all their clothings once except the last two girls (yuna kotomori and lovu chan). You should know this if you've played the game but just shoot all of the squares with numbers until the clothings start to glimmer and then shoot the clothings to remove them.

these achievements simply require you to play against every girl an extra time with one hand mode activated. It only unlocks after beating the girl once so you are forced to play against every girl twice. you don't have to do the last two girls after the M.I.L.F girl.

You have to use every powerup once. These are the extra weapons on the side of your sip suh as a misile lasers and also the shield buff. Also make sure to equip and use the special attack "JUSTICE LASER". Also try to walk into a mine once.

Have a nice day I hope the guide helped in some way or another. Let me know if you have any questions or suggestions for improvements.