Unlock the following bonuses by performing the corresponding tasks:
BONUS - HOW TO UNLOCK All cars - Collect 11 Bonus Stunt items while completing Challenge 8. Note: The Bonus Stunt Items are the purple balls with silver rings rotating around them. All worlds - Find the Hidden Key while completing Challenge 18. The yellow key is in the Mines, across a trestle at the end of a tunnel. All gadgets - Intentionally hit 25 Barrels while completing Challenge 7. Laser upgrade - Note: You must get an "A+" rank when doing the following. Complete all challenges, then unlock the "Timer Speed" cheat. Set it to 10% speed. Change the difficulty level to very hard then complete Challenge 18. Get the "A+" rank to unlock the "Laser Upgrade" cheat. Unlimited ammunition - Intentionally hit 50 Barrels while completing Challenge 18. Unlimited health - Intentionally hit 179 Barrels while completing Challenge 17. Unlimited turbo - Collect 8 Zappers while completing Challenge 4. Timer speed - Intentionally hit 13 Detour Signs while completing Challenge 15.