Nice idea, but could use some work on the execution.
Starting by fighting the boss is really cool, if only frustrating due to its long arrival with the alarm, along with the instant ultralaser while you're still fidgetting to get the hang of it. As others said, a bit too much health, and there is a safe spot between the lasers where you can simply wait and shoot. Given the idea, it may have been a bit better to have the boss shoot less projectiles, and less spammy with the lasers, but being more punishing with the standard shots and maybe being a bit more complex than shooting in straight horizontal lines, as to get the player to move around and really understanding the gameplay.
Only went up to wave 11 after that, due to having way too much projectiles at the same time, while also having the ship downgraded to stage 1 so it took ages to kill enemies.
The tutorial was waaaaay too long and descriptive, I had forgotten half the infos by the time I got to the end of it. Try being more concise, and use as few pages as you can.
As for the visuals, I liked the boss' design, the sprite was really nice, as are the player and the foes.
However, the purple bullets tend to be hard to see against the backgrounds, the bombs and power down are a bit lackluster as to understand what they are.
Small detail also, but the white circles, that I assume are stars are annoying. They are almost as big as bullets, which is really distracting for the eyes and makes the game way messier. Also they shouldn't go in front of the ships, that's a bit weird.
Overall, if you're still a beginner, which I assume, given that it's only your second game on itch, that's a pretty nice work and you should keep on creating games.
Also, a bit of advice for your next jam : be more careful with the scope.
Your game would have been more enjoyable if it had something like half the waves, but with more polish.
A personal line that I use is to go with a concept where I can have all the code by the halfway point of the jam at worst, so that all the remaining time can be use to add sound, vfx, bugfixes, and improving.