Arena

Arena is a game mode featuring two sub-modes: Sandbox and Competitive. These game modes are available from the main menu, and allow for local multiplayer with up to four players fighting and eating in a variety of Arena maps. Most creatures, objects, and maps of these modes are initially unavailable and must be unlocked by finding collectibles spread across the Single Player mode.

The Arena menu presents you with a variety of options to customize your experience. Game mode is selected at the top, underneath which are a series of icons that allow you to toggle which players are active. Maps can be set in the sliding menu to the left - only the ones unlocked will be available to play on. Immediately next to maps are several sliders that change the number of points rewarded for completing objectives, including slaying of unlocked creatures. Below the character selection are check-boxes to enable PvP (player-versus-player) combat, aggressive enemy AI, and other mode-specific settings.

Sandbox
Sandbox mode allows the players freedom in crafting their own arena experience, with a readily accessible arena editing feature and customizable objectives. The menu screen of Sandbox allows for detailed control of the arena rules, such as settings for the rain timer (ranging from 30 seconds to 10 minutes, or forever) and the end-conditions of a given round: playing until a desired score, playing until the rains come, or no restriction.

In-game, players are allowed to switch freely between a spawn editing mode and live play. The locations of creatures, food items, weapons, and even player spawns can be controlled in the editor. Slugcats can only spawn at tunnels, and will spawn randomly if one is not selected. In the bottom right of the editing interface is the option to randomize creature spawns, switch between preset spawn configurations, and to initiate live play. Switching between live play and the editor is also possible via the pause menu.

Competitive
Competitive mode encourages quick hop-in hop-out sessions where players compete towards objectives including food consumed, time survived, and creatures slain. Competitive mode is setup for the creation of round playlists, wherein several maps can be played sequentially without interruption. A second slider near the map selector allows for customization of that playlist, with the option of randomizing all maps chosen.

A checkbox to the right determines the number of times each map in the playlist will be visited. Above that slider are check-boxes to control the ability for players to spear each other and the aggressiveness of AI. Even the length and pacing of a round can be controlled, with duration of cycles able to be set from 30 seconds to 10 minutes and the quantity of creatures ranging from non-existent to overwhelming in quantity.

Unlockables


In single player mode, throughout the map are unlock tokens which make certain maps and creatures available in Arena mode once obtained. Unlocks are shared between both Sandbox and Competitive. There are 34 playable maps, of which Amphitheater, Frame, Levels, Platforms and Warehouse are always available. There are also 59 objects and creatures available, of which the (used to set player spawn points),, , ,  and  are unlocked by default.

Trivia

 * Arena was added in the 1.5 update.
 * The first three color options are modeled after the single player difficulty modes. Nightcat is unique to Arena mode.
 * All Slugcats in Arena mode have the physical aptitude and abilities of Survivor, despite the differing colors.
 * Additionally, none of the Slugcats have access to back-spears.
 * Players enter Arena mode via tunnels normally representing room transitions. These tunnels change into shelters as soon as the end-condition is met.
 * It is possible in sandbox to de-select all players and play. No Slugcats spawn, allowing to iterate upon creature-to-creature relationships without player interference.
 * Arena unlocks do not persist between save files, but do not get deleted from resetting a save file.
 * If a 's mask is removed in competitive mode and it survives, it has a chance to reappear in subsequent rounds. Additionally, if the demasked Vulture is not killed, it has a chance to reappear in subsequent rounds.
 * Aggressive mothers often show up in future rounds and target whoever angered them.
 * can be tamed in arena with reduced difficulty, and re-spawn in subsequent rounds for as long as they stay alive.
 * On normal behavior settings, reputation is tracked for each Slugcat, it persists through competitive rounds and it is increased and decreased by a factor of 1.5x compared to single player. It has the same effects as usual with a few exceptions.
 * s stay hostile even at maximum reputation levels.
 * Some s may still harass high reputation Slugcats with rubbish.
 * On aggressive AI mode, reputation is set to the lowest value of -100 every round.
 * On the darker maps, each Slugcat glows as if they have eaten a Neuron Fly.
 * Early in development there were plans to have an integrated level editor in arena mode so that people could build their own arenas in-game. This was quickly scrapped, but the separate level editor application was made publicly available after release.