To warp to level 5, first get to level 3-1. When you enter the first door, fall all the way down. You have to be in the middle as you fall. When you stop, you will find a platform with a door. Enter the door, then look for the potion in the grass. Pick it up, then throw it on the ground, enter the door in cyberspace, and go into the vase and you will be at level 5.