CONFIRMED: It's possible to beat the game with one soldier. Preferably a Grey Knight or Mercenary, and farming isn't really necessary, since you only have to level up/upgrade one soldier.
13 '''trys'' (you may want to fix this). @Axis_Vampire, no bug; minimum size is 20% (after getting hit, your size will half, but quickly recover, use this to your advantage). Also, the blue blocks have a size of 35-45%.