Enter this password in the password screen in the main menu.

Effect	Password
1-1-2 with Unlimited Lives	YZTP
1-2-1 with Unlimited Lives	MS5W
1-3-1 with Unlimited Lives	BKZ4
Infinite lives (play from the very first level)	M!K3
Start at 1-3-1 with unlimited lives	MS91
Start at Level 2-2-1 with 6 lives	SP77
Start on Level 2-2-1 with unlimited lives	94MC
To enable debug, press L, R to select the function, level, select new game to access	MSMC