I'm pretty sure any game you play will allow you to switch the WASD for the dpad. Is there any game you know of that doesn't allow for remapping?
Quite a few, I'm sure. Most really old dos games, platformers mostly: Keen series for example, I don't think allows you to change the keys.
Fortunately, these all use standard the arrow keys anyway. If not, DosBox can be used to remap the keys to what it does use. If DosBox can't, then the keyboard driver can.