I've completed your game! It's a fun challenge that's also fair. I love seeing the different alien portraits in each wave and I think there was 2 times when I managed to deal out 2 damage which was cool. I also like the special options afterwards. If you were to continue on your project, I think adding animation and background music could improve your game 
Viewing post in PEMDAS jam comments
CONGRATULATIONS!
That's so cool that you played it all the way through.
I don't know if you looked at our setting page (it has no settings at the moment), instead I listed all the things I want to add to the game and animation and music are at the top of the list.
So, thanks for the great feedback, I will definitely get to work on an update after the Jam is over!