Same problem here
This has happened with me multiple times in Dungeon Defenders and Stand 'o Food 3. I can play maybe 5-10 minutes before it just crashes to the home screen. No force close. Samurai Warriors 2 has the same problem I think, but I haven't played that very much yet.
This is very disappointing, as one of the reasons I wanted such a fast phone was for the gaming capabilities. I really hope that Samsung fixes this soon.