For example, in Super Metroid in old Tourian to the right of Mother Brain's room, there is a teleporter directly to brinstar, of course this wasn't the case in the original game at all, SM also excluded the whole section to the right of the teleporter which would be how you actually would get into Tourian into the original game.However a curious fact is that if you actually look at the map of the original Metroid, you will see the elevator you start the game in Brinstar is located exactly below Tourian, specifically to the right of Mother Brain, so from a map perspective it would make perfect sense there would be in fact an elevator there like SM has.Then you have Zero Mission which completely ignores the Super Metroid layout and also makes so the elevator from Brinstar actually move you to Cratera and not Tourian.
