In Space Marine, the player engages enemies in both melee and at range from a third-person point of view.[4] The player character, Demetrian Titus, has a regenerative force shield (i.e. the "Iron Halo") that can absorb initial damages but require certain cooldown before recovery.[5] When his health gets low, performing stun moves can allow Titus to trigger a quick time event known as "Execution" which results in an instant kill and regaining a portion of his health.[6] Titus is accompanied by the characters Sidonus and Leandros for most of the game, though some missions are performed alone.[7] The game features a "Fury" meter that, when filled up, grants rapid health regeneration and stronger melee attacks.[5] This ability can later be upgraded with purity seals to improve its duration, the rate at which it recharges, and the effectiveness of ranged attacks (slow motion when zoomed, a faster fire rate and increased damage).[5]
The starting weapons include a combat knife and a 8-shot bolt pistol (which is semi-automatic but has infinite ammunition), though the player can acquire other more powerful weapons, hand grenades, ammunitions and medkits along the game. Upgradable ranged weapons include boltgun and heavy bolter, stalker bolter (which functions as a sniper rifle), melta gun (which functions as a combat shotgun), plasma gun, and also a new weapon not featured in the tabletop game known as the Vengeance Launcher, which is a grenade launcher that shoot remotely detonated sticky fusion grenades;[8] upgradable melee weapons include chainsword, power sword (acquired via DLC), power axe and thunderhammer. In certain stages of the game, Titus can also acquire a jet pack which provides short bursts of aerial movements and deals damages within a small area upon impactful landing.
The game's main antagonists are the Orks and later the Forces of Chaos. The Orks are an alien race of brutish looters. The Forces of Chaos are traitor Space Marines who follow the Gods of Chaos, and can summon daemons that live in a parallel dimension known as The Warp. Portals conjured by the Traitor Legions allow daemons to enter the battlefield.[9][7][
In additional to the single-player campaign, the game also features an 8-vs-8 online multiplayer mode, and a 4-player cooperative survival mode called "Exterminatus", both of which have a class-based gameplay that dictates the type of weapons a player can choose to equip with each loadout.
