Serious Sam Double D XXL turns the series’ monster-blasting into a side-scrolling shooter for two. You and one friend can play its campaign together on the same PC, sharing one screen as Sam Stone and his ally Huff fire at Mental’s creatures. Expect fast shooting, small platforming challenges, and weapons stacked into an increasingly ridiculous tower.
A co-op campaign on one screen
The original Serious Sam Double D was a single-player, 2D offshoot of the first-person series. XXL is the expanded edition: it adds Huff as a second playable character, new missions, guns, enemies, upgrades, challenge content, and additional stages. The core idea stays the same. Sam runs through comic-book-like environments, jumps between platforms, searches for hidden routes, and shoots anything Mental sends into the scene. With a friend, Huff joins the same campaign, so you tackle those rooms and boss encounters side by side instead of taking turns.
The camera keeps both characters in one shared scrolling view as you cross platforms, crowded rooms, and boss fights. Sam and Huff stay on the same route through the campaign’s side-scrolling levels.
Both players share one local co-op session on the same PC. When a friend joins remotely, Steam Remote Play Together lets the host run the local game while streaming its video and audio and returning the guest’s input. A guest can use their own controller or share the keyboard and mouse, depending on the host’s settings. You still share one screen, so the remote session preserves the same two-player layout.
The PC co-op setup supports one player on keyboard and mouse with the other on a controller, or two controllers. Controller support is partial, with Xbox 360/XInput specified in the requirements.
Build a weapon tower
The Gunstacker is the main twist. In most shooters you choose one gun at a time; here, connectors found through the levels let you attach weapons into a stack of up to six and fire the whole combination together. You can combine different types or stack several copies of a favorite, then change the build as you find more guns and connectors. A shotgun can sit beneath a laser, a rocket launcher can top a stream of bullets, or you can pile on repeated versions of a single weapon. The fun is seeing a stack fire as one improvised wall of bullets, with pickups changing how Sam’s next firefight unfolds.
Weapons behave differently, so changing the stack changes more than its size. Some spread shots across nearby enemies; others send explosives through a crowd or keep firing along a narrow line. Some upgrades change how a gun behaves or add practical effects such as greater ammunition capacity or slower falling while firing. The shop lets you spend level currency on modifications including bee-firing shotguns, Prism Lasers, and the returning Cannon. You can try different combinations as the campaign expands your options. The game’s humor also reaches into those upgrades: a familiar gun may behave in a deliberately silly way once modified. If a six-gun tower sounds like a messy solution to a problem, that is rather the point.
The stack has limits. Every attached weapon draws on ammunition, and firing a whole collection at once can empty supplies quickly. A heavyweight build may erase a large enemy before it reaches you, but it can also leave less ammo for the next wave. Changing the guns in the stack changes both its ammunition use and its spread of fire; reusing one setup keeps those bursts familiar.
Run, jump, and clear the route
Each stage mixes forward movement with bursts of combat. Enemies arrive from both sides, from above, or through entrances that suddenly become active. You jump across gaps, climb through platform sections, and search corners for weapons, upgrades, currency, and secrets. The camera scrolls sideways through three broad settings that include ancient Egypt, Pompeii, and prehistoric environments. Some stages change the pace with platforming, secret hunting, or brief vehicle sections. A stretch of open ground can become a compact firing line, while vertical paths give you ledges and hidden pockets to investigate between encounters.
The campaign is a sequence of hand-built levels rather than one endless arena. You move toward exits, clear required threats, and face larger set pieces and bosses along the way. Enemy bodies can become footholds for reaching higher ledges, while a throwable Jump Pad launches Sam toward elevated platforms or secret pockets. These tools connect the game’s shooting with its platforming, and Sam and Huff cross those same routes together.
XXL adds twelve challenge rooms with survival or objective goals and six head-to-head arenas where Sam and Huff face one another. In the campaign, both characters fight Mental’s forces together; the arenas switch the focus to direct competition. The arenas let you bring weapons from the campaign into a duel, while the challenge rooms set shorter goals against the game’s enemies. These modes offer separate ways to use its shooting and Gunstacker between campaign runs.
Progress and replay value
Secrets can contain health and armor upgrades, ammunition, extra weapons, or comedy finds. Side paths therefore hold practical supplies alongside the game’s more absurd discoveries.
After finishing the campaign, you can replay it on a higher difficulty with unlocked weapons and upgrades carried forward. That New Game Plus-style progression changes what is available at the start of another run. Challenge rooms and head-to-head arenas offer separate activities beyond the story. The main campaign is compact, with secrets and optional modes to revisit.
The atmosphere leans into the oddball side of Serious Sam. You travel between ancient Egypt, Pompeii, and prehistoric environments, trading fire with familiar enemies such as Gnaars and Biomechanoids. XXL adds creatures such as Torcher Kitties, Chimputees, and Vuvuzelators, plus four distinct boss encounters. The palette is loud, the animation has a deliberately rough, cutout feel, and enemies burst into exaggerated gore. Short scenes use broad jokes and self-aware dialogue rather than a serious story. If your friends like chaotic action with cartoonish absurdity, that tone is part of the appeal; if you want a polished, restrained presentation, the visuals and humor may be a harder sell.
Is it a fit for your group?
XXL is a compact arcade shooter for two friends who enjoy fast action, platform challenges, and absurd humor.