This is a really fun game with a lot of potential. a game you should check out if you haven't already is Sanctum 2, it does most of what you have going on with this game and I feel you could take a lot from what that game did.

I do enjoy the simplistic art style you have going on, it is nice, but it also looks like most mobile game ads.

since the shops don't take money to buy, there should be a button that you can access between levels.

if the game gets some tweaks made to it and gets released as a full game, I would absolutely buy it.

Good job on making this, it has a lot of potential, and i for one will be keeping an eye on it for future updates.

I really like tower defense games and I do enjoy this, but I feel like it's trying to do too much. There is nothing wrong with depth, but I prefer pathing/tower building to using the hero at all. I beat the level 5-10 recommended level with no hero upgrades. I really enjoy Orcs must die, but I feel like this game does so little in terms of how much you need the hero that it would be better left on the cutting room floor. I would prefer more tower options instead of your hero talents, but that's just my opinion.