Version 1.7 - Added Checkpoint

Ok, I know I said that 1.5 was going to be the last gameplay update, but I was still a bit bothered by how hard the Finale was and didn't want to leave it at that.

There is a now a checkpoint at the 50% mark. I have also fixed a small inconsistency with how the Mouse enemies work in the Finale. Please let me know if there are any other issues.

Ok bye.