Descenders

The Forest is the second world in Career mode. To reach this world you must complete the boss level (indicated by a skull icon on the world map) in the first world you begin career mode in, highlands. Each session is unique and randomized, so the number of levels needed to be completed vary.

You begin with 4 lives and gain an additional life for completing bonus objectives (one for each track) as well as completing the special medic camp track in each world. Take it slow and easy, avoiding any difficult jumps or obstacles and simply making it across the finish line. Even the boss jump in the Highlands that has the rider jump over a train is not necessary to complete - just pass the ramp and under the bridge to the finish line and you will unlock this achievement.