Serious Sam Double D is a 2011 side-scrolling shooter game developed by Mommy's Best Games and published by Devolver Digital. The game follows Sam "Serious" Stone traveling through various historical settings to destroy the horde of his nemesis, Mental, and its teleportation beacons. As Sam, the player navigates 2D levels and can use the "gun stacker" to create vertical stacks of up to six weapons that are fired simultaneously. Enemies appear from all sides and their corpses can be used as platforms.
Announced in March 2011, Double D was created as part of the Serious Sam Indie Series to promote the release of Serious Sam 3: BFE. Devolver Digital requested a "Contra on acid" and designer Nathan Fouts modeled the game after Mommy's Best Games' first release, Weapon of Choice. Double D debuted for Windows in August 2011. Serious Sam Double D XXL, an expanded version, was co-released by Mastertronic for the Xbox 360 via Xbox Live Arcade in February 2013, introducing more content and a local cooperative multiplayer mode. This version was ported back to Windows and released in October 2013 as a free update for the original game.
Both versions of Double D were met with mixed reviews. The gun stacker was well received, although a lack of depth was noted. The sound design was praised. Conflicting opinions were raised regarding the game's writing, level design, music, and visual style. Its repetitiveness and technical issues were criticized.
Gameplay
Serious Sam Double D is a 2D side-scrolling shooter with run and gun, platform, and exploration elements. It is played as a twin-stick shooter with a gamepad or with a keyboard–mouse control combination. The primary objective is leading Sam "Serious" Stone through various historical settings, fight enemies from the horde of his nemesis, Mental, and destroy teleportation beacons it placed. The antagonist is General Maxilla, who is leading the horde on Mental's behalf. Sam, as the player character, traverses confined levels, most of which have a primary route leading to the right, while others have branching paths, and some include puzzles. Enemies approach from multiple directions and attack using varying behaviors: some engage in melee combat, others bear ranged weapons, and some act as suicide bombers.
Sam can use up to four weapons of each of eight types, which can be collected throughout levels. By default, he brandishes one machine pistol. As part of the "gun stacker", using collectible connectors, the player can stack up to six weapons vertically and fire them simultaneously. Eight stacks can be configured and at any time altered and swapped between. Each gun has a separate type of ammunition, of which explosive projectiles may inflict self-harm on the character. Once acquired, a portable jump pad can be thrown repeatedly. It remains where it lands, including on walls, and Sam and enemies bounce off it. Among other techniques, wall jumps can be performed using it. Sam's movement direction can be adjusted mid-air.
Upon death, enemies' corpses persist in place and become navigable platforms. Some level sections continuously spawn enemies until enough corpses pave the way, either vertically or horizontally, for Sam to proceed. Some collectibles are hidden, among them unlockable challenges that pit the player against a certain number of enemies with a pre-determined arsenal. The game automatically saves the progress at checkpoints, while quicksaves can be performed manually.
In Serious Sam Double D XXL, each type of weapon has four distinct upgrades. These, as well as ammunition, can be purchased from shops using currency dropped by enemies that are killed by player characters. For the local multiplayer mode, a second player, assuming the role of Dan "Huff" Huffington, can join in at any time and engage in cooperative gameplay. If either player character goes off-screen, he is automatically transported back to the other. If one of them dies, the other can resurrect him by collecting crosses the corpse emits. Two players can also engage in head-to-head combat in a separate mode. Of the twenty-one levels in XXL, three employ auto-running gameplay using vehicles.