Good idea... BUT the horse and the 2 towers maxed won the entire game. To easy. Needs more thought. The only reasonable part was the cost of upgrades. For the power upgrades gave, the cost was OK. 2/5
Great game, nice idea. Seems to be wel balanced, til the end, when you can easily have over 3000 gems. Maybe a hard mode, where a death or warp costs you a random ship part?