Congratulations on your first game jam and your submission. The game itself works very good.
Maybe a good idea to show the player which enemy is faster or more health. Also show the health of the generator somewhere on screen instead of only the generator itself. I've lost as I couldn't find the generator in time due to the action on screenm ;-).
I like the alien invasion increase/decrease on the music. Maybe unintended but it a nice effect.
By the way: the sound is loud, try using the audio mixer in Unity (did that the first time wrong as well ;-) )