Nice!! Randomized wave survival with upgrade branches makes this a fun game to play and replay. I did have a very hard time reading the font, to the point where I felt like I didn't have enough information to make a decision at some upgrade screens. If you fix that and maybe also do a balance pass with enemy behavior (would sometimes get screens of entirely stationary enemies who couldn't hurt me because they shot in a straight line), you'll have something that feels great to die and retry to.
Good work!