Thanks for the feedback!
Funny you mention being overwhelmed by the amount of stuff you can build since I already tried tackling that problem by hiding everything that's not unlockable yet. Maybe I should limit it even more. At the start you shouldn't really need more than towers and fences.
Making the enemies behave in a unique way is indeed something I wanted to do but I didn't have enough unique abilities to make them all different. Sabotaging is something I thought about but dismissed because I thought it would be too strong, I might give this a try in the future.
I think stealing coins from the base/tower wouldn't work because it means you didn't put up enough defenses and then you would have less money to build your extra defenses which seems like a guaranteed loss.
The weather is an interesting idea. I really like to change the map over time (like enemies destroy obstacles and leave dirt trails eventually). Working with sun/wind/rain might give me a reason to play with the amount of water on the map. I might give this a shot next time I work on it.
I'm glad you liked it, now I guess I need to figure out how to get more people to see/try it!