Guess how I beat the last level? Maxed out everything and used all of my 16 swords (with the use of 1 health and 1 speed) and it killed the last boss, no guys lost. nice
There should be more levels after the last one, I was doing really good, and I won, so I had to restart. That was really annoying, so there should be an extra few levels, or a free play level where you can choose who you want to go against.
There should be hot-keys for upgrading so you don't need to loose focus on the game. For example, numbers 1 to 9 for however many upgrades there are. That would be helpful to have, but it isn't vital so you don't have to do it.