Thanks for playing my game! When I came up with the game concept, I had brainstormed a rough idea for each of the rats that I wanted to implement. Then based on that, I thought of some combinations I wanted the player to use the rats in that was different from other levels, and designed a level around it, and doing some trial and error to make things feel good and intuitive. This was my first puzzle game, and I tend to make games a bit too hard, so I'm delighted to see that you found the difficulty acceptable. The timing level seems to be the hardest level for most people - I do regret making that one a bit too hard. But for the most part I'm glad you enjoyed it! :)