I play with the 0.3.1 version, I think too that it should work with the 0.5.1 version, but the cursor is too slow and we can't take saves to use them on the 0.3.1 version...
You can skip the rats bug in 0.3.
You must only wait some minutes (when you have win the rats game) until it saves the game automatically, then, the game will continue.