this is a very good game, i liked the strategy behind using an orange shot vs a blue shot. the upgrades are quite nice the music is decent and the visuals look very good. the upgrades are meaningful and i feel like they add something to the game. the enemies each have very unique mechanics and i like that.
now onto criticisms:
the bullets can be kind of hard to control, i do like that there is 2 forms of them though and it's quite nice!
in my opinion it is a cool dynamic to have your own bullets hurt you but i think personally that it may be better if that wasn't the case. this is mainly because by wave 3 you have so much to worry about that it is very difficult to also have the constant threat of worrying about your own bullets.
enemies by wave 4 are very overwhelming and hard to deal with. by that i mean its kind of near impossible to kill a lot of enemies unless you one tap them. (i also think that i had some skill issuing in upgrading)
by wave 6 i ran into the issue of it was very easy to kill enemies but my own bullets hurt me so bad that it nearly killed me. (i died to my own bullet on wave 7 ): )
some upgrades like the lethal spin confuse me a little. on upgrades i think that they could scale a bit better.
the health ui looks a little off to me. that could be personal preference though.
the foreground is a bit boring and could use some touching up, the background is confusing because i cant tell if its floating in the sky or if this is an island.
i think the game could benefit a lot from adding upgrades outside of the main levels. adding progression and maybe a small story. i also think maybe the enemies should scale slightly with the players damage, its nice to become op but it is also a bullet hell. generally though i think this is a very good and solid game for a game jam. considering we all only had 7 days to make a game this is one of the better ones. (sorry if my criticism is too harsh!)