This really isn't my type of game, so I don't know how useful I can be but...
How to make it more immersive:
- I fully agree with LeviathanLaw's suggestions!
- Add some interactive points (e.g., a speed boost, attacks against opponents, etc.)
- When jumping over obstacles award players for the quality of their jump. Encourage player's to just barely clear obstacles as it will reward those who challenge themselves and encourage improving skills.
- Make each environment different for the player in someway (e.g., the snow level has ice that makes jumps longer, the desert level has quicksand that makes jump height lower)... I don't think messing with jump mechanics across an entire biome would be good as it would be frustrating to have to learn new timing each time, but little patches here and there would add some variety and make each area feel different.