Gungeon Online

Online co-op for up to 4 players in Enter the Gungeon over Steam (play with friends anywhere, no port forwarding) or LAN (same home network).

Very early alpha — side project. Built as a hobby in spare time. Expect bugs, desyncs and crashes; every player needs the exact same version; back up your saves first. No support or guarantees.

It can do this so far (all experimental):

Playing together

• Host a friends-only Steam lobby and invite up to 3 friends through the Steam overlay, or accept a friend's invite
• Host or join a LAN game by IP address, or find LAN games automatically
• See the other players: character, animations, gun, pet, ghost glow, status effects and name tags
• Party list on the right side of the screen: every other player's character, hearts and armor
• Host-led runs on the same seed: same floors, run start and end, Quick Restart from the death screen

Shared world

• Enemies: shared health and deaths; the game in charge of a room decides each enemy's attacks and movement, so everyone sees the same fight
• Status effects on enemies (freeze, charm, fire, poison, slow, bleed) happen in every game
• Bullets look the same for everyone, items and synergies included: tints, size, bounces, piercing, chain lightning, orbiting and spiral bullets, gun muzzle and reload effects
• Companions (all of them) and orbitals (Guon stones...) show for everyone
• Same room decorations in every game; bullets, thrown items, blanks, floor effects, tables, breakables and rolling barrels
• Shared money, keys and pause; optional PvP and split money
• Teleport to fights: when someone starts a fight, everyone else is pulled in (on by default)
• Tougher enemies with more players (+50% health per extra player by default; stacks with Loop The Gungeon)

Deaths and drop-outs

• Co-op deaths: become a ghost, get revived from a chest or with the Cultist's Friendship Cookie
• A player who drops out keeps playing as a bot with their gear; when they rejoin, their character is handed back. Only one bot at a time: the host's game has room for one extra character, so if several players drop out, only the first gets a bot
• Take a Break: a bot plays for you until you touch the controls again

Other mods

• Loop The Gungeon: loops, the loop's time tube and its difficulty settings are shared with everyone
• Custom Characters, Expand The Gungeon and Gungeon Go Vroom settings are matched where needed

Requirements

• Enter the Gungeon (Steam play needs the Steam version of the game)
• BepInExPack for EtG (your mod manager installs it automatically)
• Every player needs the same version of this mod

How to use

Use the Multiplayer button on the main menu, or press F8 in game to show or hide the Gungeon Online window.

Your name: type it in the Name box and click Save. Leave it empty to use your Steam name.

Steam:

1. Host: click Host on Steam, then Invite friend and pick a friend in the Steam overlay.
2. Friends: accept the invite in Steam.

LAN:

1. Host: click Host on LAN. The window shows your LAN address (like 192.168.1.20:27460).
2. Friends: click Find LAN games and pick the host, or type the address and click Join.
3. The first time you host, Windows may ask whether to let Enter the Gungeon through the firewall. Allow it on private networks.

The status changes to Connected and shows your ping.

Keys:

• F8: show or hide the Gungeon Online window
• F6, or Take a Break in the pause menu: let a bot play for you until you move again
• F7: accept a guest's request to restart the run

Settings

In BepInEx/config/gungeononline.multiplayer.cfg (or your mod manager's config editor). The host's rules apply to everyone:

• PlayerName: the name others see (empty = Steam name)
• ToggleWindowKey, TakeABreakKey, AcceptRestartKey: the keys above
• Port (LAN): the UDP port for LAN games (default 27460; host and friends must match)
• PvP: players' bullets hurt each other (default off)
• HalfMoney: split boss money; a boss's money counts 1/players, since it drops in every game (default on). Enemies' money always counts in full
• TeleportToFights: pull everyone into a fight someone starts (default on)
• ScaleEnemyHealth, HealthPerExtraPlayer: tougher enemies with more players (default on, +50% each)
• ShowPartnerName, ShowPartyList: name tags and the party list (default on)

Troubleshooting

• Each game session is saved to BepInEx/GungeonOnline-logs in your mod profile (the last 10 are kept). After a problem, send the newest file there; it isn't erased when you open the game again. Gungeon Online's lines start with [Gungeon Online].
• If the game freezes, the same file says where (look for [FreezeWatch]). The host's file matters most.
• LAN game not found? Make sure all PCs are on the same network and the firewall allows the game, then try typing the address instead.
• Things look different for different players? Make sure everyone runs the same version of this mod and of any other gameplay mods.

Credits

• Built on BepInEx and the game's own Steamworks.NET
• Built with help from Claude (Anthropic), an AI assistant

License

MIT

Support

If you enjoy this side project, you can support me or follow my other projects:

• Ko-fi: https://ko-fi.com/alexjustalex
• Patreon: https://patreon.com/AlexanderVazquez
• GitHub: https://github.com/AlexUnknown37