Dristone mode is where it's at. You got robbed if you got US version. Dristone mode works like this
You get 100 air, for every 1 you drill, you lose 1 air.you get dristones along the way which you can use when you please, they do things like "change all blue to green blocks" "air + 20" etc etc. Its pretty fun.
Mission driller is frikin hard. I assume that you must use the powerups to progress to the really deep levels..... I can't beat the 800 level at the moment. Normal or Dristone mode.