Finished level 810 a few days ago, waiting for more! Would also love to know how I can go back to the start of the map and improve my helper mice levels. Is there an easy way to see the whole map at once and jump between levels, or do you have to scroll back through each level individually?
Pets are only dropped once you clear all of the black boxes using the bombs. The sooner you can do this, the more moves you will have to save the pets that finally drop.