Player go through a Checkpoint tile (29 in tele layer)
He fall in a Check-Teleporter tile (31 in tele layer)
Player is teleported to the check-TO (30 in tele layer) that have the same number as the last Checkpoint.
Thus players are teleported to the last checkpoint he passed, regardless of whether he made the map in the right direction or not.
Adding a checkpoint system for teleporters :
Tele tileset may need some improvement.