Helldivers 2 can get pretty scary at times, but it's fundamentally an action-first game. The same could largely be said of its original, top-down progenitor, although the vision-limiting perspective of the first game made it much tougher to know when you were running directly into even more trouble than you were leaving behind. Putting an even more spooky twist on proceedings and reminiscent of Valve classic Alien Swarm is new roguelike game Ammo and Oxygen, and a free demo just launched on Steam.