When on the arena select screen in VS., Hold the Z Button on Basic Arena, or No Man's Land to play in alternate graphics for those stages.
In the outer world, when Harry asks you to join him to follow him to the bathroom, say no. Then Harry will ask you again, say no. You will stand outside with Sergei and Marcia for a while. Harry will then come out saying he had to fight in the bathroom.
Just before you leave for the outside world a second time,continuosly select the option "I'm not going,".Eventualy,Harry will stop asking and they will all go without you.Then the secret message appears,then you go back to the same point before you leave.
Once you are in the developer's room, talk to the robot (that looks like the one at the training gym). The game will save, and the next time you go to a parts generator, you will get the Oil Can robo part collection.