Strider

Three continues:
Press A, C, B, C, A, Start at the opening screen.

Constant robots:
Collect two robots and find a container with a robo-panther. Open the container, but do not touch it. Allow your character to get hit and lose a robot. Touch the robo-panther to activate it. After a short amount of time, the robo-panther will leave the two robots with you. They will remain even after you lose a life.

Secret room:
Move past the gorilla in level two to the section containing spinning gears. Jump on one of the containers, then jump into the rocks that are above. If your jump is timed correctly, you will become caught in the rock and appear in a secret room. Keep jumping until this occurs. Defeat the Phantom, then climb the wall to the right to exit and continue normal game play.