If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
Grab and stash as much cash as you can without getting caught. Your marks will chase you, so be crafty about your escape! If you get trapped, jump behind a dumpster and change into a disguise.
Arrow keys - To move.
Z - To jump.
X - To steal.
Arrow key Down + X - To stash cash/get disguised.