3D Movement
Don't Starve Elsewhere introduces real 3D movement, including jumping and falling. That is a change from the top-down movement of the original Don't Starve games, and it is one of the systemic pillars Klei has called out directly in the game's announcement materials.
Implications
The multi-tiered world is only possible because the character can move up and down through it.
Platforming-style encounters become viable for the first time in the series.
Fall damage and vertical pathing enter the survival decision space.