This is a fun game. This kind of game is often too repetitive but you managed to make a lot of different ennemies with unique behaviours. Well done!
There are however a lot of small design problems :
-Before the jump boost, it is very hard to dodge. Even with the boost, the character feels clumsy. It could be fixed with a faster movment speed and better jump physic.
-The attacks of the level 2 boss are almost impossible to dodge, and he have a ton of health and deals a lot of damage. I managed to beat him by attacking him from the back but it felt cheesy. The level 1 and 3 bosses hovewer are well designed.
-The projectiles just disapearing at max range and the lack of feedback when the ennemy is hit make it hard to know if we hit or were just out of range. The range felt a bit too short too.
-It is also hard to aim, maybe make the projectiles faster and increase the size of their collision boxes.
-Camera is too slow and doesn't show the platforms when we have to jump downward.
- I dont understant the point of the browser version with only 1 level. It's a gam jam there is no need for a demo. Either put the full game on the browser or dont make a browser version at all.
I hope this is helpfull.