Spelunky 2 can be played with up to four concurrent players, either locally or online.
In the character select screen, up to three other controllers can be connected, where they are then asked to select which spelunky they wish to play as.
Local Multiplayer does not use split-screen, and instead the first player is given a white flag, indicating that the game’s camera will follow them, regardless of where the other players go. If the player with the white flag dies, the flag is passed to the second player, and so forth.
Online Multiplayer is accessed via the “Online” tab in the main menu. Players can invite other players to their game via a room code and either begin a run with them or search for other players in a public lobby.
Crossplay is available between PC, Xbox, and Nintendo Switch, with players in any of those platforms able to find and join each other. Crossplay with PS4 is planned, although due to complications with Sony it is not yet present.
Nintendo Switch Online is not required to play Online Multiplayer, as Spelunky 2 utilizes its own servers from studio Blitworks rather than Nintendo’s paid servers.
Seeded Runs are unlocked by collecting the wooden Idol found on the Moon's surface in the Camp, allowing play on a predetermined run by entering a specified seed.
It is impossible to extract the seed from a run generated in the standard Adventure Mode, as levels in Adventure Mode generate on the fly.
Seeds reset with every game update, although it is possible to visit older iterations of a seed by downpatching Spelunky 2.
Generation is almost entirely consistent on the same seed, even across different copies of Spelunky 2.
If a Level Feeling generates in a level, it is ensured that it always occurs in that level. This includes dark levels and echo levels, which occur in levels even if the spelunker beats the previous level in under 30 seconds.
Crates, Presents, Chests, and other openable loot always contain the same contents within. Items with a normally randomized durability (such as Mattocks) have a determinate amount of uses, remaining consistent.
If the spelunker’s actions affect level generation on (such as killing one of The Three Sisters or Madame Tusk, preventing their structures from appearing later), the differently generated area is also predetermined by the seed.
Spelunky FYI has a list of seeds that can be submitted to by users.
In the Daily Challenge, every player in the world is given the same seed and a single opportunity to play through it.
A leaderboard for the Daily Challenge is available, showing how far players made it through the seeds, and an option to sort by how deep players made it, how much score they racked up, or how fast they completed the Daily Challenge.
Completing the Daily Challenge by either winning the game or dying makes it unplayable until the next day (00:00 UTC), where the given seed and accompanying leaderboards reset.