Don't know if it's been posted before, but there is apparently a bug in build 152 where you remain invincible after getting a clock. The only way to get rid of the invincibility is to save/quit or use cheats and turn it off manually. First time I happened I thought it was a random error but it's happened several times while I was playing... damned annoying too.
A bug I noticed...
Beta 152 bugs don't go here. Go to the custom quest contest and post it there. That said, I'm going to copy this over to the beta forum for further consideration.