Thanks to wipeoutjack for looking into the game files to find out about the actual requirements for the Platinum Medals in this game:
Cone Zone - 80 Scoops (You don't need to wait for the countdown, as soon as you have 80 you can topple the stack, thanks KilleDragon for pointing that out)
Veggie Guardin - 2200pts (You don't have to beat the boss mole if you reach this score quickly)
Skip Skimmer - 180 Skims (Just use regular stones, avoid special stones like Heart, Dolphin and Flying Saucer)
Pose Mii Plus - 900pts (Don't lose a single life)
Trigger Twist - All Stages 26000pts (You can lose all 3 lives in the Dinosaur Stage once you reach this score) Unlock Ninja Stage - 1000pts UFO Stage (You can only take damage from the boss, so just complete the level as quick as possible) Unlock Dinosaur Stage - 2000pts Ninja Stage (You can lose all 3 lives after reaching this score) Unlock All Stages - 2500pts Dinosaur Stage (You can lose all 3 lives after reaching this score)
Jump Park - Beat Level 4 (Time limit is unknown)
Teeter Targets - Beat Level 30
Spooky Search - Level 3 1600pts
Wind Runner - Level 3 200pts Unlock Level 2 - Level 1 100pts Unlock Level 3 - Level 2 150pts (Pay attention to your bonus timer for Level 2 and 3 to know how many rings you need to pick up, Level 1 you can just race to the end as fast as possible picking up enough gems along the way)
Treasure Twirl - Level 4 8000pts Unlock Level 2, 3 and 4 - 4000pts Small Gems - 10pts Big Gems - 100pts Bronze Chest - 800pts Silver Chest - 1200pts Gold Chest - 2500pts Gas Tank - Score depends on how much gas remains, each bar as a 100 point marker out of 10 bars (Level 4 is the only one that requires all 3 chests to be picked up, Level 3 can be done with just the gold chest as long as you don't get hit when climbing back to the surface. Level 1 and 2 just pick up both Gold and Bronze chests and fill up your gas tank)
Flutter Fly - Level 4 900pts Unlock level 2 - Level 1 200pts Unlock Level 3 and 4 - Level 2 and 3 400pts Rings - 5 and 15pts with no 4 leaf clover, 15 and 30pts with 4 leaf clover. Balloons - 50pts Each Balloon Remaining Flower Strands - Combo System 10pts - 70pts, max score 280pts Remaining Time gets added to your score (Level 1 you can just head to the goal without picking up anything, Level 2 and 3 is similar but you can pick up an extra balloon, rings or flower strands for safety. Level 4 you need to pick up almost everything, at least 4 balloons needed when reaching the goal. You can ignore the crows in all levels, but you might need to get rid of them in level 4)
Space Shuttle - Beat Level 30
Should anyone want to speedrun this or any other medal category, I recommend getting an SD card to save the game onto it with all the Minigames unlock, thus enabling you to plan out your own route.
Before you start unlocking the games, use a Guest Mii as fresh Miis are required for runs. To avoid earning medals, you can just fail cone zone, veggie guardin, skip skimmer and pose mii plus as you would in an all levels run. For trigger twist, don't shoot anything and let the mothership defeat you, in Jump Park, reach the goal with 3 minutes on the clock at least to avoid earning the Bronze medal. In teeter targets, let the ball fall off constantly to run out of time and lastly in spooky search, don't collect any ghosts and let time run out.
Once you have all minigames unlocked, go back to the Wii Menu, go to the save data menu for the wii and copy the save file of the game to your SD card. Now you're all set to run this game as fast as possible and make up your own routes, just remember that if your run dies at any point, make sure to delete the save file on the console first before copying the save file on the SD back onto the console, because unlike Wii Play, any medals earned in this game are stored in the game itself instead of the Mii you use.
imma add that you can also die Cone Zone just after getting 80 points, not needing to mantain the cone for the time of waiting after the 60-80 round but wow this is very usefull information right here
