Here is the full list of all 15 Mushroom Men: Truffle Trouble achievements.
Complete the tutorial.
Fall off the world ten times in one level.
Speed run of less than 2 minutes on any Garden level.
Jump on a trampoline block 100 times in a row.
Kill an enemy while being shot out of a cannon block.
Complete a level on Hard difficulty without allowing the princess to get in range of grabbing Pax.
Complete a level on Normal or Hard difficulty without falling off the world.
Transform into every one of Pax's forms.
Launch Pax out of a cannon block.
Use a trampoline block.
Complete an entire environment on three different difficulty levels. (Bedroom excluded)
After being launched from a cannon block, fly the distance of 1000 blocks.
Kill 50 enemies.
Place a block on top of another block 20 times.
Move 10 blocks.