Since you can't really make use of Teleport Rocks getting to places like Oblivion 2 and 4 is a very tedious experience (big maps with lots of buffer zones). If you want to venture to the FM (RIP FM button) or somewhere else to chill you will take some time before you get there, specially for those who don't have a movement skill like Teleport or Double Jump. Overall the Oblivion maps feel so isolated and far away from the rest of the Maple World. My suggestion is adding a Time Lane selection to the Portal at the Three Doors Map. This way you can select which part of ToT you can go to: Memory Lane, Road of Regrets, Oblivion. Of course you would only get moved to the start of each part (Frozen Past, Burning Past maps). This way it's probably not needed to code a restriction for those who havent unlocked the map first, as moving to the following map would move you out to the last map you unlocked.
