Cool idea!
I like that there is a bit of variety and extra steps into making a wave. Having the extra things like number of units per module, as well as the bonus they will get if they are placed there are very fun to play around with. I find that most of the "you are the boss" games are fun when they let the player have a bunch of decisions to upgrade their arsenal and become super strong. I think there is a lot of room here to add more effects, and unit types.
There are also some issues that should be changed, like being able to keep watching the fight after you die. Or the issue of the game crashing when you touch the player with a shield (I'm guessing that was the cause)
I think that the shooting units were way stronger than the charging melee ones, since they can keep doing damage while the melee ones die after doing damage. So having a bit more balance on this could help, maybe melee units can keep attacking multiple times?
I would also be interesting for units to have some form of "value" that if they are killed gives the player money. So you wouldn't want to make your entire team the strongest unit, since the player will get a lot of value from clearing it out.
The visuals were nice a simple, but they worked very well.
Nice job!