This game is known as Sokoban, warehouse keeper, or Box in.
From Wikipedia, Sokoban is a type of transport puzzle, in which the player pushes boxes or crates around in a warehouse, trying to get them to designated storage locations. 'Sokoban' was created in 1981 by Hiroyuki Imabayashi, and published in 1982 by Thinking Rabbit, a software house based in Takarazuka, Japan.
1. Only one rat can be pushed at a time
2. A rat cannot be pulled
3. The rabbit cannot walk through rats or walls.
Fixed: "Submit Score" bug