I like the idea a lot! Tower defense games are always fun.
Once I defeated the first wave of enemies, no more seemed to spawn (even after waiting 20 seconds) and I didn't get a win/loss message so I'm not sure if I did it correctly. I was also surprised to realize I needed to click to place the tower after pressing a number key. However, the towers seemed to function as expected and I enjoyed watching the archer tower fire arrows. I would've been happy to keep playing if the enemies spawned.