Challenges list of computerfan0
Skippin' a Hop
Hydroplane Field : Reach the southwestern corner by taking at most 1 jump, without driving the track backwards

Dryver
Hydroplane Field : Complete the track in less than 1:45 without touching any puddle

Soggy Cash
Hydroplane Field : Collect all coins in less than 45s

Fast as a tortoise!
Very Good Track : Complete the track in less than 2:30 in 25cc class, with Bowser

Box Smasher
Very Good Track : Hit all item boxes in less than 45s

Beat the Staff Ghost
Hydroplane Field : Complete the track in less than 1:32:071 in Time Trial mode, in 150cc class

Impossibly... Doable?
Larry's Scratchy Castle : Finish in the 1st position in 500cc class, in impossible mode

Unlucky Items
Larry's Scratchy Castle : Hit all item boxes in less than 13s

Beat the Staff Ghost
Very Good Track : Complete the track in less than 1:14:180 in Time Trial mode, in 150cc class

Beat the Staff Ghost
Larry's Scratchy Castle : Complete the track in less than 1:02:258 in Time Trial mode, in 150cc class

Super (Short) Circuit
Larry's Scratchy Castle : Complete the track in less than 40s in 200cc class, in Time Trial mode, without falling

Falless Guys
Very Good Track : Complete the track without falling, in 1st place
