Please allow key changes! and maybe an Undo?

[omega13lives]

Can you please program in key changes so players can choose which keys do what? I really don't like using Shift and Enter, because sometimes I hit the wrong key and then it's all over. It would also be nice to be able to use keys on the left side of the keyboard, for lefties and when my right hand starts to hurt.

Also, the same as the original Sokoban, it really sucks to be almost done with a level and then accidentally push a critical box against the wall. In fact on my PC, sometimes the characters move 2 spaces instead of 1 even though I've turned down the repeat value.

Please, oh, please!