You don't need to guess. The goal is to leave no open ends on each level, and there's a logical way to go about that on each level. In addition, there is autosave. Use arrow keys to move between completed levels.
It seems like every level is pretty easily winnable by spawning a handful of tanks and then dropping repeated artillery barrages on the opponent's spawn point until nothing but infantry is coming out. The game is beautiful and a great concept, but the gameplay needs a lot of work for this to be a classic
 "Glean"){kind=icon}
 "loops of zen"){kind=icon}
 "Escape from really boring island"){kind=icon}
 "Jumper"){kind=icon}
 "Shadez: The Black Operations"){kind=icon}