This is a strong one! Overall it's well-executed, especially for the time constraint. You should both be proud. :)
Things I liked:
- Great music, and a large soundtrack especially for a jam game
- It's a great concept for a bullet hell, well worth expanding into a larger game. It's interesting that you're upgrading the boss instead of yourself!
- Graphic style and sound look great, and the overall artistic direction feels polished.
- I like that there are many choices to upgrade your boss.
Problems I had:
- My biggest problem is that the game gets pretty repetitive. The boss battles start out at a medium difficulty rather than easy and doesn't get that much harder with the upgrades. The battles aren't unreasonably long, but over and over again, the same battle gets old. I think a little less cooldown on the player's bullets, or the ability to do more damage, would help speed things up a bit.
- My controls briefly got stuck walking to the right. I'm not sure how. I fixed it by pressing the right arrow key again and letting it go. I have 2 monitors and I was playing in fullscreen on one of them.
- It would be nice if you could see your character's hitbox. There is currently some guesswork as to whether a bullet will hit you. The way Deltarune does it is clever: your hitbox shows up as an overlay when bullets are near.
- Also, the bullets are so large that sometimes it's not feasible to skillfully duck and weave around them; you have to try to outrun them or get as far away as possible.
- When you die, it seems that your progress (the enemy difficulty) is reset to 0. I wasn't a fan of this. This also happens if you go past the max in level 2.
- Music on both levels loops incorrectly
Wishes for future development (if you decide to do more):
- I would love it if you could upgrade yourself instead of just your enemy. Maybe the enemy gets WAY stronger with each upgrade, but you can also use the difficulty points to buy upgrades for yourself. That way it's like the Vampire Survivors thing where the adversaries are ridiculously overpowered, but so is the player.
- I would also like to see the option to either upgrade past the max or just stop at the max. Like once you reach 300 difficulty points, you can move on to the next level, or you can choose some of the upgrades you skipped last time, and get other rewards in the next level for doing so.
Great job on this entry. Again, it's got a fun concept!