The game is certainly rough around the edges but that's to be expected in a game jam.  I like the concepts but the project may have been a bit ambitious for the time frame.

• The shop didn't seem to do anything for me (This may have been a bug?)
• moving the character feels stiff (I think the game would have been fine just locking the character in place)
• By moving in any one direction for a few seconds you can guarantee that all enemies  approach from the same side
• you can just spam click to spawn enemies and immediately shoot them for points (maybe make missed shots not give points?)
• there is no reason to ever aim close to the player, the shots may as well have had a set distance
• the music is a bit loud (but it's better to be to loud than to quiet)
• and all the UI/menus look blurry
• when you die many particles are spawned lagging the game
• The background gives no sense of movement (just needs some pattern instead of a black screen)
• credits have no back button meaning your stuck

I know this sounds like a lot, but some of it is just nitpicking.

That being said I don't think this is a horrible game. You have a working game that fits the theme of the jam.

• The shooting works well
• The particles look good
• Screen shake is never bad (might have been a bit much tho)
• the menus all work
• Controls are shown to the player
• I like the concept of missed shots becoming enemies
• There are sound effects

Overall completing a game at all is an accomplishment and something to be proud of. (Only 3 out of the 10 people that entered this jam submitted something)