Colour Codes

not really pink but pink tiles: you can just go trough them
red tiles: impassable (with the boosters, you bounce back to the booster and then to the block you came from, or the block behind the booster?)
yellow tiles: they push you in the opposite direction that you're facing (so basically like red tiles if you're walking normally). If deactivated, it becomes grey.
green tiles: you can just pass, if you bounce on them from a booster, you basically just do another boost (like the minecraft slime blocks!)
blue tiles: you can pass through them, unless it has an active yellow tile on it's side, in which case it acts like a yellow tile. You also can't pass if you taste like orange, as piranhas come out (acts like yellow tile)
orange tiles: like pink tiles, but they change your flavour to orange. purple tiles: you slide through them, they change your flavour to grape (lemon in UT)
boosters: like the boosters in Hotland. Has some indication of how many blocks it pushes you.
pink tiles:
cyan tiles: freeze you, make you slide to the next square, ignoring it's effect and making it freeze (of course unless it's a red or yellow one or something, it has to be a tile you can land on) and the next after that. (if you walk on a cyan tile with a yellow tile on the other side, you slide to the yellow tile, back to the cyan tile, then back to the one you came from, and THAT tile becomes freezed... or better: the cyan one freezes when you pass trough)
brown tiles:
dark red:
dark green:

Bonus Effects:
a little ice sprite on the tile: you just walk on this tile, ignoring it's effect. When you step on it, the ice reduces it's health by one and the sprite cracks. When the life is 0, the ice breaks (tile stops being frozen) as soon as you leave. I think frozen tiles caused by cyan tiles should have a health of 1, but maybe 2 would be interesting.
fruit: gives you the flavour of the fruit (and the fruit is consumed?)?