Hi, taken another look at my game and reading a few other posts I think I've narrowed down the issue - at least with the game I thought was corrupted.
The issue with the 'ouch message" still comes up in all games, but the game not working at all problem seems to be related to me adding using the maps block. When I turn off the save game block, everything is fine again. I'd read elsewhere in the forums that saving a map as a game attribute may cause issues, and I've noticed the same symptoms - I have a splash screen with various game attributes showing, and as per other posters, get random strings of text that get longer on each reload when viewed in the browser .