if you click an upgrade with your left mouse button, your right button, and your mouse wheel, it'll think you've "clicked" on the upgrade 3 times and will make your profit x27 for each business instead of only x3
LOL, i bought all of the upgrades on the 2nd day by flying the rocket at the least amount of power on the first day, then the money displayer will say "money: NaN $" and that all give unlimited money :D
somehow i skipped the first encounter with the red demon things and went straight to where the "old and wise" guy had to choose between the three doors O_o
glitch, when you're destroyed and exit to the upgrades, then press play before the "YOU'RE DESTROYED" thing goes away, it skips to the day that you're on.