Most twin-stick shooters serve up ammo and enemies in equally infinite proportions, embracing the shoot-everything-that-moves formula that has come to define the genre. Helldivers is different. While the hordes of enemies are just as endless, limited ammo and the ever-threatening presence of friendly fire create a more challenging and calculated shooter.
Full disclosure: I haven't beaten Helldivers yet, and neither has anyone else. Arrowhead's less subtle take on Starship Troopers tasks players with "defending" Super Earth by exterminating a trio of extraterrestrial races, and that galactic conquest is a community-driven campaign that takes 4-6 weeks to complete. While this meta-structure is a clever addition, it's ultimately little more than window-dressing for the frantic, co-op focused action. You play Helldivers for the thrill of each individual battle, not the outcome of the larger war.
Helldivers offers a simple-yet-satisfying gameplay loop. You select your warfront (bugs, cyborgs, or the alien Illuminate), a randomized planet to battle on (from one of 12 difficulty levels), and then complete missions to level up your helldiver, unlock new gear, and upgrade your existing armaments before jumping back into the fray. This basic structure has a surprising amount of variety; each of the three alien races features different enemy types and fighting styles, and objectives offer a healthy number of variations on taking and defending points, blowing up enemy encampments, and escorting. Three planet types (jungle, desert, and snow) mix things up further, as do special hours-long attack and defend events that pop up every couple of days and award bonus XP.
Like Diablo III, each procedurally generated map in Helldivers feels unique and familiar at the same time, as does the moment-to-moment gameplay; I grew comfortable mowing down countless swarms of hostile aliens (ideally with three friends at my side) while sprinting from one objective to the next. Brief pauses in the action are typically used to call down strategems from the heavens to aid you in combat and hopefully keep you alive for what always seems like a last-second extraction.
Strategems are the real draw of Helldivers' deep progression system and gameplay variety, supplying you with everything from rocket launchers and airstrikes to your own overpowered mech. Surviving higher difficulty levels requires coordinating who brings what to the fight and working in constant unison, but even on lower difficulty levels, Helldivers doubles down on communication and teamwork; you're just as likely to be offed by an inaccurate squadmate or your own automated turret as an enemy ambush.
Even after the unlocks dry up, the challenge and camaraderie that Helldivers offers makes it hard not to attempt "just one more mission" with your friends, a proposition made all the more enticing by the inclusion of four-player couch co-op. I still don't know how the community-driven galactic campaign will shake out over the coming weeks, but contributing to the larger war effort is just one more welcome excuse to enlist.