i thought i replied to this already but i think i closed my browser before i posted it.
First off, great start!
It's no secret that i love tower defense games, and this one looks like it's going to be very good.
One of the tricky things to get right with the tower defense games is to make them easy to start, but have it so it really requires some strategy to do well..
We recently posted about one of very best tower games (Onslaught) and you should be sure to check it out, because it shows how to really make a game both easy to play but also "deep" in the sense of drawing you in to experiment with different strategies (
https://www.donation...index.php?topic=8183). I think that might be your biggest challenge at this point.
The idea of having different towers for different classes of enemies is interesting, but i couldn't quite figure out when i would use dif towers and where i would want to place them differently.. and the fact that each tower could get the same upgrades also made me feel like i wasnt as compelled to explore with different kinds of towers.
The ability for enemies to take different directions has a great potential i think (Curator Defense, another tower defense game, used this idea to great effect), but i couldn't figure out how the monsters in your game made their decisions.
So i guess my general feeling was it had great potential but i want to see more features and game design which makes me feel like i want to really explore to figure out different kinds of strategies..