Thanks for the feedback. I'm happy to hear that you find it satisfying to shoot multiple enemies quickly, I like it to :) Letting players try powers before starting the game could be a good idea, I'll try it.
For the final boss, was it clear to you that you could not avoid the fireball attack and the only way to stop it is by shooting at the fireball? some people seem to have problem with this, I'll have to work on that too.
Yes I only started learning in October, this one is probably my first original game. (still need to follow step by step from a lot of tutorial videos though :P) Thanks for all the support from everyone, it is really encouraging for me :D