Here is the full list of all 27 Voxel M.R.T. achievements.
Defeat 100 enemies total.
Defeat 1.000 enemies total.
Defeat 10.000 enemies total.
Have 50.000 gold at once.
Have 100.000 gold at once.
Have 300 wood in your stockpile.
Have 300 stone in your stockpile.
Have 300 food in your stockpile.
Have 300 beer in your stockpile.
Have 300 clothes in your stockpile.
Defeat an ogre at least at hard difficulty.
Defeat a wyvern at least at hard difficulty.
Defeat a viking boss at least at hard difficulty.
Destroy a spawner at medium difficulty.
Destroy a spawner at hard difficulty.
Destroy a spawner at crazy difficulty.
Level your character to level 10.
Level any unit to level 10.
Destroy a spawner at nightmare difficulty.
Defeat the Halloween map at least at hard difficulty and medium wave speed.
Defeat a mummie at least at hard difficulty.
Get your first skillpoint.
Get all skillpoints that are available.
Defeat the bad Santa at least at hard difficulty.
Destroy the "Ogre Tamers" castle.
Complete the first campaign mission.
Beat every campaign mission at least at difficulty "Crazy".