• Talk to G until he reveals his sled. Put it in your inventory
• Use your spy phone to go to the Ski Mountain.
• Use your spy phone to go to the Sport Shop. Click Teleport again.
• Talk to G and the sled will appear again.

Basically you can duplicate the sled using this glitch. I don't know if it has any speedrunning use.

I don't think it has any use, since you only need one to destroy it and advance to the next part of the mission. I've also encountered glitches while running All Missions, but the two of them are the ones that kill runs.

More silly stuff involving the black puffle.

You can force the black puffle to disappear by:

Opening and closing your survival guide while the puffle is on fire, then leaving the area.

Exiting and re-entering the cave, which moves your puffle to the left until it goes out of bounds.

Trying to exit the cave, which moves your puffle to the right. I'm not sure how this happened and wasn't able to reproduce it.