ErrorTrap does catch a lot of errors in your game, but definitely not all of them. In doing so, it can prevent a number of crashes, but again, not all of them. For example, there is nothing that ErrorTrap can do if you get an out-of-memory crash. On the other hand, it WILL clean up some crud from your game, and thereby "postpone" such a crash, but if your game runs out of memory in spite of that, there's nothing it can do to prevent that.