On level 1-3 Bash through the 1st set of spikes to the left of the 1st suspended platform fall down the passage and break the Question mark block to warp.
Warp to Pac-man
On level 4-4 right before the collapsing pillars climb under the 1st overhang and break through the wall, fall down the passage and into pacmans mouth to warp.
Warp to Pitfall
On level 2-1 pull the 1st vertical platform to the left, climb the ceiling and drop down using heavy to break through the ground fall down the passage and into a room with a giant pitfall Harry sprite to warp.
Warp to the isle of the dead
On level 3-4 in the room where the skulls fly out of the ground run and grab onto the 1st skull platform that shoots out, ride it up into the air till you see a platform marked 666, jump to that platform to warp.