EDIT: Better way of doing this is on youtube.
(To make it work for any size/resolution you will need to move the cameras)
In the last part I showed how to jump through platforms.
Now I will show you how to implement the side teleporting. (example)
This code is attached on the player:
You need to make 2 empty gameObjects, with the names LeftColl and RightColl, and attach a 2D box collider to them. On the 2D box collider check isTrigger.
This piece of code will set the colliders to the right coords.