Thought this was great! There was a good variety of different attack types, and I had a good time coming up with good tactics with the different attack mechanics. In particular, I thought the difficulty was really well balanced, which is really tough to manage without much playtesting. I found it challenging without being frustrating.
The way you found unique attacks for each VTuber that reflected their personalities, and also had unique mechanics, was really great. Vedal with a big machine, Evil with her harpoon, Anny with her brush, etc. I wasn't quite sure what Neuro's attack was supposed to be though. They were all clever enough that I'll give you the benefit of the doubt that it was probably a reference to something though.
The theme felt a little tacked on though. The dates were "in the past" relative to the game's current date, I guess, but since they were still in our future they might as well have been random. It would have been nice if they tied into some actual history of the VTubers they were unlocking. Had a ton of fun playing though! I meant to play a bunch of games, but I just ended up playing Neuro Wars for hours.