Too many ads. This would be a decent defense game if it wasn’t for the ads after EVERY level, and EVERY time I paused the game. On top of that, there are only three free units in the game. If you want to get the improved units, you MUST purchase gems with real world money. As it is, this game is garbage. If the developer reduces the forced ads and provides a way to earn gems in-game, this could be a very solid game. More skills and castle upgrades would be nice, as well.