Checkpoints
You will normally respawn at the start of the current course when you run into a hazard. You can change your checkpoint at the dog houses found along the path. Stop at one to either watch an advertisement or pay gems to set a new checkpoint. Instead of spending gems immediately, try to determine what is coming up. If there is a difficult area ahead, it is usually followed by a dog house. Those are good places to spend gems.
Hazards
While in motion, your body is stretching. If your body is in the way of moving hazards, it will get hit eventually. Try to work your way around hazards to keep your body safe from harm; or land on a platform so that your body retracts. You will be safe after landing, because your body cannot take damage while retracting.
