Never happened to me....
I've never made it to the halfway mark...
*KING of All jokes lame*
Seriously though, I've only created two 'games' the first one was called the 'Adventures of Cat', cat looked like a box and walked into a wall (that was just about it.) I quit cause the game just sucked, I mean really bad.
The next game, I was forced to quit, considering that TK had some funky error with it and it wouldn't let me use it... then my computer crased and I had to reinstall everything :angry:
So, I've never quit a game due to another game, but I have for other reasons ^_^