Mario Kart Wii/Unlockables

The unlockables below are listed in the order that they can be optimally unlocked (e.g. by beating all 50CC circuits, and then all 100CC circuits, all 150CC circuits, then all mirrored circuits). Time trial rewards are listed last, but can be completed at any time.

Cups
Each unlockable circuit has to be unlocked separately for 50CC, 100CC, and 150CC.
 * Star Cup: get a silver trophy (second place) or better on Mushroom Cup and Flower Cup.
 * Leaf Cup: get a silver trophy (second place) or better on Shell Cup and Banana Cup.
 * Special Cup: get a silver trophy (second place) or better on Star Cup.
 * Lightning Cup: get a silver trophy (second place) or better on Leaf Cup.
 * Mirror Mode: get a gold trophy (first place) in all 150CC cups.
 * Star Cup in Mirror Mode: get a silver trophy (second place) or better on Mushroom Cup in Mirror Mode and Flower Cup in Mirror Mode.
 * Leaf Cup in Mirror Mode: get a silver trophy (second place) or better on Shell Cup in Mirror Mode and Banana Cup in Mirror Mode.
 * Special Cup in Mirror Mode: get a silver trophy (second place) or better on Star Cup in Mirror Mode.
 * Lightning Cup in Mirror Mode: get a silver trophy (second place) or better on Leaf Cup in Mirror Mode.

Characters

 * King Boo: get a silver trophy (second place) or better on Mushroom Cup, Flower Cup, Shell Cup, and Banana Cup, or complete 750 races.
 * Diddy Kong: get a silver trophy (second place) or better on all eight normal 50CC circuits, or complete 450 races.
 * Baby Daisy: get a one star rank or better on all eight normal 50CC circuits, or complete 1,950 races.
 * Dry Bones: get a gold trophy (first place) in the 100CC Leaf Cup, or complete 1,050 races.
 * Mii Outfit A: get a gold trophy (first place) in the 100CC Special Cup.
 * Daisy: get a gold trophy (first place) in the 150CC Special Cup.


 * Time Trial rewards
 * Birdo: complete 16 time trials (with any time) or beat 250 people while playing online.
 * Funky Kong: unlock four "fast staff ghosts" (expert staff ghosts), or win 25 Wi-Fi Ghost Races, or complete 2,250 races.
 * Toadette: complete all 32 time trials (with any time) or win 1,000 Wi-Fi races, or complete 3,150 races.
 * Baby Luigi: unlock 8 "fast staff ghosts" (expert staff ghosts), or win 100 Wi-Fi Ghost Races, or complete 3,150 races.

Karts and Bikes

 * 50CC rewards
 * 50CC bikes in 50CC Grand Prix: get a silver trophy (second place) or better on all eight normal 50CC circuits.
 * Super Blooper (medium kart): get a gold trophy (first place) in the 50CC Leaf Cup.
 * Piranha Prowler (heavy kart): get a gold trophy (first place) in the 50CC Special Cup.
 * Cheep Charger (small kart): get a one star (or better) rank in "the entire Retro Grand Prix on 50cc" (all 50CC Cups).


 * 100CC rewards
 * Shooting Star (heavy bike): get a gold trophy (first place) in the 100CC Star Cup.
 * Zip Zip (medium bike): get a gold trophy (first place) in the 100CC Lightning Cup.
 * 100CC karts in 100CC Grand Prix: get a silver trophy (second place) or better on all eight normal 100CC circuits.


 * 150CC rewards
 * Quacker (small bike): get a gold trophy (first place) in the 150CC Star Cup.
 * Day Tripper (medium kart): get a gold trophy (first place) in the 150CC Leaf Cup.
 * Honeycoupe (large kart): get a gold trophy (first place) in the 150CC Lightning Cup.


 * Mirror Mode rewards
 * Dolphin Dasher (medium bike): get a gold trophy (first place) in the Star Cup in Mirror Mode.
 * Jet Bubble (small bike): get a gold trophy (first place) in the Leaf Cup in Mirror Mode.
 * Phantom (large bike): get a gold trophy (first place) in the Special Cup in Mirror Mode.
 * Blue Falcon (small kart): get a gold trophy (first place) in the Lightning Cup in Mirror Mode.


 * Time Trial rewards
 * Magikruiser (small bike): complete 8 time trials with any time.
 * Tiny Titan (small kart): unlock a "fast staff ghost" (expert staff ghost).
 * Spear (large bike): unlock 12 "fast staff ghosts" (expert staff ghosts).
 * Sprinter (medium kart): unlock 24 "fast staff ghosts" (expert staff ghosts).