The Tower on the Edge Nice art; terrible design.
Spikes blend in with environment art too much. Chosen aspect ratio isn't that great for most screens and could be reduced. Needs minions to practice on before jumping straight into a 'boss' fight. A boss on a tutorial level isn't a great idea either unless you plan to use it in a story. Also, needs some story IN GAME or world exploration to give more depth for players to latch onto.
It's a good starting point but it needs a lot of work and development. Keep working on it.
Visual Online -logic game 
