Hey there! It's interesting to see someone who managed to get their hands on and mess around with Unitale. I saw the trailer for it a while back, but for now I'll just be sticking to good 'ol Danmakufu 
If you intend to continue working with Unitale, though, you should prooooobably figure out a work-around for that massive slowdown you got from spawning a lot of bullets. This ain't Touhou, I'm afraid... :ohdear: Perhaps you could use larger bullets and less-dense patterns, so "less is more." But if you WOULD like to continue making danmaku-intensive fights, I would highly recommend checking out Danmakufu ph3. If you know what you're doing, you could make just about anything you'd want, breaking past whatever limitations the Unitale engine may have. However, there is quite a bit of a learning curve for learning how to do what you want in Danmakufu, and it looks like you're already getting a handle on Unitale. So in the meantime, I wish you luck with future battles!
Danmakufu's on my do-right-now list; Unitale is just cool for writing bullet-intensive stuff because i do Touhou and i'm absolutely in love with Undertale
my goals with Unitale scripts are floating somewhere around "replicate spellcards in an appropriate fashion" and "write something original at some point, jeez" - i'm definitely going to be doing more original things in Danmakufu when i get into it so no worries on yet another BBWaP replicant haha
Unitale as of right now is in a very early stage so for good functionality, i'd recommend waiting a couple of versions before trying it out - e.g. "lasers" aren't really feasible yet, since the current version handles hitboxes by simply drawing a rectangle around the sprite (it's being fixed up into proper transparent-pixel masking soon)
the slowdown is definitely a tricky thing to tackle but the dev's stated that in some hopefully imminent version, manual bullet "despawning" will be possible, so just throwing an "is this bullet out of bounds" handler should work miracles
thank you for responding <3
