Steel Survivor: Tank War

You get one tank and a field full of them. Twelve missions across three sectors. Each one is a run: you start with a single gun and build the tank you finish with, picking one card at a time between waves. Nothing carries into the next mission except what you bought in the garage, so every mission is a fresh argument about what to build. Cover is real. Enemy armour cannot see you through a wall and you cannot shoot them through one either. Drive into the open and the whole line wakes up at once. Three stars a mission. The first is for clearing it. The second is for finishing with half your hull. The third is for finishing without calling a repair. Stars open the next sector, so the campaign asks you to go back for the ones you left. Clear the first sector and endless opens: no end, no stars, waves until they take you. Four tanks, six weapons that evolve into something worse for everyone else, a garage full of permanent upgrades, and national colours painted on the armour. No internet needed. No account. Play it on a plane.