Played through level 9. Fun little small game. The waves were really the best part the colors and ricochets are cool and lovely and the hits feel meaty and impactful. The enemy deaths were nice too. I love a big enemy death not something you see too often. Could probably have made the game a bit faster and have it build level over level. It wasn't clear if it was getting harder or not. Also wasn't sure there was an upgrade mechanic, you mentioned it in the description, was the yellow thing upgrading me? Felt like a classic game jam game really fun to play. I also liked how my little blobby dude moved that was cute. Also weirdly your sounds were in your folder not sure why they didn't link up
 
PS: you packaged your virtual environment and your git file. You probably didn't need all that, not that it matters just thought I'd mention it! Also if you want your sound to play you need to actually trigger the play method on them in sound.py play method something like 'sound=self.sounds[name]  sound.play()' with proper line break and stuff. Might also put like a check around it in case the sound isn't loaded so pygame doesn't crash if a sound gets misloaded.
Right now your play is a stub I think. (I have not done pygame in years tho)

love the gameplay! audio is missing but all in all very fun and solid game.