During play press and hold any of the following:
'ALT', 'Y', ANY NUMBER (0-9)------------Skip levels
'ALT', 'Y', 'I'----------Turns off sprite collision
'ALT', 'Y', 'K'-----------------Increase ammunition
'ALT', 'Y', 'L'----------------------Increase lives
'ALT', 'Y', 'M'--Removes game sprites and platforms
'ALT', 'Y', 'N'--Replace game sprites and platforms
'ALT', 'Y', 'Q'---------------------------Game over
If you jump onto the notice board next to the mission 1 entrance and push up, you'll be able to collect 4 extra lives.
On mission 3, jump along the 4th platform, jump up and keep pushing up and you'll climb the wall. When you reach the top, walk to the left and keep going until you reach the edge of the screen. There you will find 10 magnifying glasses, one gun, a round of bullets and an extra life.
1-"KUIRFR" | 3-"RDRKBA"
2-"BEIFCF" | 4-"LYLSUA"