Charlie Gun, a wave-based 2d shooter

Charlie Gun (and the Robot Space Cowboys from Hell) is a 2d platformer shooter about upgrading your weapons and self to defeat an ever-increasing onslaught of enemy creatures.
There are currently 30 waves for each of the 3 difficulty levels, and 5 maps.
I would really appreciate feedback on the game! 🙂

Play it here: https://murpyh.itch.io/charlie-gun

Here’s some gameplay footage if you’re curious:
https://www.youtube.com/watch?v=KirEFdiZyaI

Source: itch.io