100% run will take forever to make. The 8 silver rabbits hunt. You need to capture at least 1 regular rabbit first though otherwise the chance of it being silver is 0%. For example:
If you capture the 3 yellow rabbits outside the castle as Yoshi, those 3 will now have a 'random silver' factor.
After capturing their silver forms, you can exit, re-enter to try and capture them again (assuming you have the luck manipulation to make them silver).
For changes:
http://www.youtube.com/watch?v=cUvVHJJZPZs
http://www.youtube.com/watch?v=NDBpHCZzYVQ
Most the gameplay changes includes:
* Tweaked wall jump mechanics as Mario
* Rocket boost start (hold the dash button and then you gain a rocket start, similar to holding 1+2 on Mario Kart Wii)
* Mini flips from Slide (Kicks) enables the player to climb up ledges, not doable on N64 version
* Long Jump to a wall jump is a bit harder this time.
* Mario's Triple Flip jump height is better than the N64 version.
* Notable level design changes in Lethal Lava Land Volcano section, Vanish Cap switch, Metal Cap switch, Tick Tock Clock, Rainbow Ride, Whomp's Fortress.
* Some of the tasks do not exist on the DS version like Tiny-Huge Island 5 secrets and Hazy Maze Cave wall jump by the rocks
* The minimum requirement to clear the game (without glitches) is 80 stars, not 70.
* It's not possible to get the 5 special coins in BBB with a single cannon blast without changing direction, etc.
* Yoshi is required for the 8 red coins in CCM and the 'updated' in the Deep Freeze Star in Snowman's Land.
That is most of them for now.
Will vote after watching the encode.