I like this one a lot! Easy tower defense mixed with resource management. Simple but engaging!
I think there's a tiny lack of polish in terms of understanding what each tower does. Like first ones have a damage tooltip, but the others don't, so do you just spam magic as you get to them?
And I don't think lvl1 towers see any light as well, there's no reason to buy these.
If you plan to expand it: it might be a good idea to work on giving each tower a meaningful effect, like usuals in tower defense: Slow, AoE, Stun, DoT, or maybe add a worker placement for more management and increased difficulty.