Fortified sets its defense in an alternate-history 1950s, where Earth faces a Martian invasion led by waves of mechanical attackers. Its pulp-comic tone frames a hybrid of third-person shooting, real-time strategy, and tower defense, rather than treating the conflict as a straightforward shooter.
Players choose among four pulp-inspired heroes, including a jetpack pilot, a space cowboy, a government agent, and a Marine captain. On the battlefield, they can build defensive structures, command an army, and personally fight with Cold War-era weapons and experimental technology. The mix asks players to balance base protection with direct combat as dangerous attackers threaten the city.
The game supports solo play as well as cooperative defense for up to four players, with its description emphasizing coordination and strategy in co-op.
