In Blue Max the player operates a World War One biplane, Upon take-off the screen starts scrolling diagonally and the only flight controls at the player's disposal are up, down, left and right, not unlike the real WW-I biplanes. It was probably named after "The Blue Max", a 1966 movie about German WW-I fighter pilots.
The game has a lot in common with Zaxxon and it's from the same programmer. But in stead of the future it's now set in some sort of tank and flak riddled WW-I landscape, where the player uses his unlimited machinegun and 30 bombs per take off to destroy as much targets (tanks, flak, buildings, boats, airbases, occassional moving vehicles and enemy planes) before landing and refitting.
Gameplay is intuïtively simple. Bottom part shows a control screen, displaying altitude, speed (always constant during flight), fuel, bombs and score. A big capital appears in case of some important event, like L for 'nearing a landing strip', P for 'Plane approaching' and W for 'Side winds'. The player can be shot by enemy flak 4 times before being killed, taking damage to the fuel system (increased fuel usage), the machine gun (occassional jams), the bombing part (occasional jams) and the fuselage (decreased maneuverability). Damage repair is automatic at the next landing strip, but needs extended time on the runway, thus increasing the risk of an enemy fighter flying over and bombing the player.