Small Arms is an action Xbox Live Arcade video game, developed by Gastronaut Studios, and published by Microsoft Game Studios. It was released for the Xbox 360 video game console on November 22, 2006 for 800 Microsoft Points ($10 USD), since then the price has halved to 400 Microsoft Points as a part of the Arcade Hits Program. 
Small Arms is a hybrid platform, fighting and shoot 'em up video game, featuring anthropomorphic animals and super-deformed people, with ranged weapons. The gameplay can be compared to Super Smash Bros., Power Stone, Contra and Metal Slug.
Similar to Geometry Wars, the player controls characters' movement with the left analog stick, and aims weapons with the right analog stick, which allows 360-degree aiming. Each weapon has primary and secondary modes, which the player can use with the right and left triggers, respectively. The player can also make characters jump or dash with the face buttons.
Small Arms features four different single-player modes: Mission Mode, which pits the player against computer-controlled players in sequence; Training Mode, which teaches the player how to play the game; Challenge Mode, where the player faces an endless stream of opponents; and Shooting Range, where the player must shoot moving targets to score points. Small Arms also features competitive multiplayer for up to four players or bots, either offline or online via Xbox Live.
Characters and weapons
Small Arms has 12 default characters, eight of which are initially available:
- Fox Claw: a runaway mutant who used to be her clan's deadlies female ninja, armed with a katana*
- Lord Peet: a chivalry fanatic, armed with a crossbow*
- Marky Kat: a former mercenary and now illegal arms trader and 3rd richest mutant cyborg, armed with a chaingun*
- Pector El Pollo: a former Mexican mutant wrestler, armed with a flamethrower and molotov cocktails
- Mr. Truffles: a famous assassin, armed with a sniper rifle and land mines
- Tyrone: a dinosaur who was raised in a research facility in the Antarctic Circle, armed with an ice weapon*
- Unit 51: an elite soldier of the Space Marines, armed with a lightning weapon
- Zöe: a 22nd century intergalactic pop-star, armed with a plasma weapon
- Billy Ray Log: a mutant tree, armed with a buzzsaw weapon
- ISO-7983: a mad killer robot, armed with an oversized pistol doubling as a missile launcher
- Mousey McNuts: a 19th century street urchin, armed with akimbo submachine guns
- Professor Von Brown: a doctor of transcendental psychology, armed with psionic powers
*available in trial version
Two new characters were made available as downloadable content from the Xbox Live Marketplace on June 6th 2007: Ivar, and Gullarp. Each character has four different costume colours and a unique weapon (except downloadable ones). However, these weapons can be exchanged for other characters' weapons during gameplay.
Levels are visualised in full 3D although the players can only move in one two-dimensional plane. Several levels have special quirks to them: the "Bullet Train" level slowly forces the players to move across the length of the train; and the "Sewer" level has a pit in the middle of the map, which closes shut and fills with poisonous gas. Small Arms launched with eight maps, and two more maps were available as downloadable content bundled with the Ivar and Gullarp character download. The two maps that are included with the downloadable content are "Iceberg" and "Village".
Small Arms has 14 achievements, which have a total of 235 Gamerscore points. It was the first Xbox Live Arcade game to exceed both the 12 achievements limit and the 200 gamerscore limit when its downloadable content added two additional achievements. A notable achievement is the "Six Degrees of Small Arms" achievement, which is unlocked by playing multiplayer with someone who has already unlocked it, and so it spreads like a virus. The achievement spreads for six generations: the members of Gastronaut Studios are first-generation players, anyone who plays with one of them is a second-generation player, and so on, up to the sixth generation. The achievement itself is worth zero Gamerscore.
Challenge x15 (10) Defeat 15 opponents in Challenge Mode
Challenge x50 (20) Defeat 50 opponents in Challenge Mode
Combo x2 (15) Kill 2 opponents in rapid succession
Combo x5 (20) Kill 5 opponents in rapid succession
Complete Mission Mode (20) Awarded for completing Mission Mode
Completed Training (10) Complete the Single Player training mode with any character
Marksmanship (25) Score over 10,000 in the 'Shooting Range'
Played 100 Matches (25) Play 100 matches either offline or on Xbox LIVE
Six Degrees of Small Arms (0) Play online to 'catch' this elusive Achievement
Won 10 Matches (10) Win 10 matches in Single Player or by playing on Xbox Live
Won 100 Matches (25) Win 100 matches in Mission Mode or Battle Mode
Won 50 Matches (15) Win 50 matches in Single Player or by playing on Xbox Live