If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
If you think your life is tough, just try walking a mile in this little mouse's shoes...
Mouse - Move.
Double-Click - Shoot.
Space bar - Jump.
X - Activate Special Power.
Collect as much food as you can. Cheese is worth 15 points. Everything else is worth 30 points.
To complete a level, collect the big piece of cheese.
Purchase upgrades between levels.
For more tutorials along the way, run across the questions marks on the floor.