Simple. Fun. The death animation was really neat and the dificulty curve felt right - easy at first, but very soon I was getting absolutelly swarmed. Awesome! On the critical side - if you sell stat first, then buy another - you get two upgrades. If you buy a stat first, then sell another, both of them get downgraded. Not really sure if you were going for just player downgrades for extra difficulty or what, but there's definitelly something wrong there.