I just beat wave 32 and I haven't spent a dime on the game. It was free when I got it. I'm pretty sure you keep your gold if you lose a wave, but I couldn't check because I'm too damn good.Is crap. A very freemium simple tower defense that is very frustrating in order to try to sell you ingame gold purchases (you can't grind by yourself, so a couple of bad decisions in the upgrade part will force you to hit a wall, having to restart the whole game... or buy some gold to be able to beat the level). I really wonder how someone like Matsuno can see something interesting in that game.