I've been thinking about some of the concerns you guys raised about the concept and hurdles for the level design, and came up with a possible solution.
What If the levels' content is based on the characters the player has left?
This means that the game would lay out the obstacles faced in the game semi-randomly a few steps ahead of the players. I'd throw in the random factor to make sure that the player still feels theb yeight of his previous mistakes throughout the entire game. But now he will get to use the characters he has left more often and the puzzles can be more geared towards certain characters. Every obstacle can still be overcome with every character, but this way I can make the default way a lot harder.
This also fits into the back story as the therapist would adapt the challenges he throws at the personalities based on which are left. Furthermore, it would seriously ad to the replay value, as each playthrough could be vastly different from the last one.
Obviously, there are some technical difficulties (especially since I'd prefer the game world to be possible to navigate without loading screens) to overcome and this means more content to design and create, but I feel like it could provide a significant improvement for the game.
Does anyone have any feedback on this idea?