@Lifepower :
You shouldn't forget that we all are just hobbyists, which means that none of us has a QA departement or dozens of PCs to test his game. I e.g. only had the chance to test the game on three different PCs (all with WinXP) and they all ran my game fine, but getting hands on more PCs with different configurations is not easy.
As for the controls it's also not easy, since the controls someone finds very easy to use are hard for another person. E.g. someone that uses to play with keyboard+mouse maybe has problems playing a game with a joystick.