The visuals and audio were really nice. It is an interesting concept but there are some areas that need work to make the game more fun.
For me at least the game didn't become as fun until I got to the later stages of the game (I was able to get to Wave 31). I think that may because the player has too much health. It may be more effective to give the player an HP boost every other wave and lower the total HP.
I also found it really easy to dodge the bullets. To make the game more challenging you could turn the bullets into homing bullets that follow the player that eventually stop after a given amount of time.
Maybe you could also have the center object that the player is connected to move around to make the game more challenging, and maybe possibly put a cap on the amount of distance that the player can be away from the center object.
The game could definitely could use some work, however the variety of enemies we're really unique and the visuals looked really good. The use of timing (especially with the explosion enemy) was also pretty challenging so that's cool.