Cool Cavern

You were on the most prestigious expedetion into mountainous territory ever organized. All of a sudden the expedition turned into horrific scenario as an earthquake shattered the snow deck you were walking on. You are now trapped inside the deep cavern the snow deck was covering. Abandon your scientific goals, survival is the only thing that counts. Be the first to reach the surface again, but don't forget to pass through all checkpoints. Some hints:
- Chests contain useful items.
- In cooperative play only one team member needs to pass a checkpoint.