Changelog

1.2.3 — Desert crypt co-op

The desert crypt — the locked room with the key and the timed trial — now works in co-op from the door to the reward room. Before this, only the player carrying the key could get in, the two sides were given different trials, and finishing one could leave someone shut in. This release changes the network protocol, so everyone in a session must update together.

Fixed:

• You can no longer be shut inside the crypt after finishing it. Stepping on the crypt's exit was mistaken for entering a sealed combat room, so the way out was closed again a few seconds later — with nothing that could ever reopen it. Whoever had not already stepped through was trapped for the rest of the level. Room exits are no longer treated as arena seals.
• The crypt key door now opens for everyone. Only one key exists in a run, and the door opened only for the player who used it — everyone else walked into an invisible wall and could never enter. The door now opens on every screen, and nobody else needs a key.
• Both players now get the same trial. The trial was picked from unsynced randomness, so one player could be hunting chickens while the other was killing enemies in the same room. The trial is now decided by the level seed, like the rest of the level.
• Crypt enemies are now run by the host. Each side used to spawn its own, so the same spot could hold a different enemy for each player. When the host killed one, the other player's enemy did not die — it just lost its AI and stood there. Crypt enemies are now spawned once by the host and mirrored, so a kill lands for everyone.
• The reward room now opens for everyone. Completing the trial opened the reward room — which holds the way out — only for the host. Everyone now gets it.
• A failed trial is now shared. A failure used to punish only the host. Now the whole group fails together.
• The trial progress bar is now visible to everyone. Only the host could see what the trial was or how long was left. The bar now shows on every screen, in your own language.
• The Protect trial's altars are now visible to everyone. The altars you have to defend — and their highlight — only appeared for the host, leaving everyone else with nothing to protect.
• The statue at the crypt entrance no longer slides around. It could be mistaken for an enemy and dragged across the room by whatever that enemy was doing.

1.2.2 — Desync, desert and status-effect fixes

A round of sync fixes from player reports: repeated maps, the loading-screen desync, invisible ghosts, and enemies that ignored a status effect. This release changes the network protocol, so everyone in a session must update together.

New:

• The four-player limit is gone. Sessions no longer cap the number of players — a fifth player used to sit on "joining" forever, on both Steam and Direct IP. There is no artificial limit now; the practical ceiling is your host's connection and CPU.

Fixed:

• Levels no longer repeat for a player who joined a host. After following the host into a level once, that player's own later levels were all generated from the host's old seed, so the same map kept coming back. Each level now rolls a fresh layout again.
• Walking ahead while someone is still on the loading screen no longer desyncs the run. If a player was sitting on the "press to continue" screen and someone else took the exit, players, map and enemies would drift apart until the next level reset it. That screen is now handled as its own state: the waiting player is led along properly, and the abandoned loading step is shut down instead of running its ending against the level that replaced it.
• Ghosts are no longer invisible to other players. Ghost enemies picked their species from unsynced randomness, so two out of three times the host and the other players disagreed about what a ghost was — the enemy stayed invisible on one side while still attacking. Ghost species now follows the level seed like the rest of the level does.
• Status effects from a weapon enchantment now actually affect the enemy. A Petrification enchantment used by anyone but the host would show the petrified look and shatter effect while the enemy kept walking. Status effects are now applied on the host, for every player, and are shown on everyone's screen — including effects the host applied, which used to be invisible to the others.
• Desert sandworms no longer throw players out of the map or freeze the game. The ambushing sandworms in the desert are now run by the host and mirrored properly: they emerge and land the same way for everyone, standing on a landing spot no longer launches you across the level, their riders are no longer fought over by two machines, and the frame-long freezes around them are gone. A non-host player can also trigger a sandworm ambush now.

1.2.1 — Endless boss fixes

Fixes for Endless Mode bosses in co-op. Updating is recommended for everyone in a session.

Fixed:

• Endless bosses can now be fought in co-op. A boss could die almost the instant it appeared: a second player's shots were bypassing the boss's entrance invulnerability, so a strong weapon could kill it before its fight even started and the stage would just move on. Bosses now stay invulnerable through their intro exactly as they do in single-player, so the fight begins properly.
• Fixed a duplicate and leftover boss health bar in Endless. A second health bar could appear during a boss fight and stay stuck on screen into later stages. Endless bosses now show a single health bar that clears correctly when the boss dies.

1.2.0 — Endless Mode co-op

Endless Mode can now be played in co-op. Both players share the same arena, waves, and enemies (the host runs the world), and the host chooses whether each player progresses independently — keeping their own XP, level, and cards — or shares one progression track with a group card vote. This release also fixes several multiplayer sync problems. All players must update to the same version before joining the same session.

New:

• Endless Mode co-op — Independent progression. Endless Mode now stays in sync between players: everyone shares the same arena, waves, and enemies (the host runs the world), while each player keeps their own XP, level, and card picks. Experience is awarded to whoever killed an enemy — the reward orb flies straight to the killer, even on a long-range shot — and the host can choose whether the kill credit goes to the player who dealt the first hit or the last hit (default: last hit). Leveling up no longer freezes the game for the other player: the world keeps running while you pick your card, and you stand safely still (invulnerable, and enemies stop targeting you) until you choose. Enemies also pick their target by distance now, so they no longer all pile onto the host.
• Endless Mode co-op — Shared progression card vote. In Shared mode both players now see the same floating cards on level-up and vote together on which one to take: aim at a card and fire to cast your vote, and your name is stamped onto the card you picked (your own stamp in gold, teammates' in red). The most-voted card wins — ties are broken by the host — and the chosen card is applied for everyone. There's no timer until someone casts the first vote, so you can take your time discussing. You can also vote to Skip or Reroll — a Skip gives each player their pass reward, and a winning Reroll deals a fresh set of cards for everyone to vote on again (the reroll card is unavailable once your shared rerolls run out). You can also vote to banish a card you don't want — aim at its dismiss button and fire; it counts as your one vote, competing with everyone's picks. If a banish wins, that card is removed for everyone (spending one shared banish) and you vote again on the rest. You can change or cancel your vote at any time by re-selecting, and the countdown only runs once at least one vote has been cast. In Shared mode you also level from one shared XP pool — everyone levels together — and the rewards a card drops into the world (loot, companions, shops, chests, and service stations) are shared too: single objects both players see in the same place, rather than a separate copy on each screen. (Shop purchases and service-station stock stay per-player for now.)

Fixed:

• The Cousin boss fight no longer freezes every player after the boss dies. In co-op the boss could lock all other players in place once it was defeated; the fight now ends cleanly for everyone.
• Fixed a level-generation desync when two players reach an exit at the same time. Taking an exit while the host was already changing levels could build the level twice and leave players in differently-shaped copies of the same map. The duplicate transition is now suppressed.
• A player who falls behind during a level change now catches up to the host's level instead of getting stuck or reloading a different version of the level.
• Steam joins are faster and more reliable. Joining by Steam ID no longer requires the host to press Invite Friends first, connects noticeably faster, and fails quickly instead of hanging on a bad attempt. — https://github.com/ryuka-dev/SULFUR-Together/issues/7
• Fixed hosting from the hub a second time failing to bring joiners in. After hosting, closing the room, and hosting again from the hub, joining players could be left behind; the host now keeps the level-generation information it needs to pull them to the hub.

Polish:

• Join flow. A "Connecting to host…" notification now appears on every way of joining, the "linked" notification no longer fires the moment you press the button, and if a joined player hasn't linked to the host a hint shows the key to press instead of silently leaving them on their own map.

Known issues:

• In Shared Endless Mode, a level-up card can occasionally show the wrong artwork or text on one player's screen. The vote and the reward you receive are always correct — only that card's appearance is affected. — https://github.com/ryuka-dev/SULFUR-Together/issues/16
• The known issues from previous releases still apply (occasional enemy snapping, boss desyncs when a client loads ahead, unsynced blood/particles/sounds, and 4+ players untested).

1.1.1 — Co-op fixes and polish

A small update with multiplayer fixes and quality-of-life improvements. All players must update to the same version before joining the same session.

Fixed:

• Players now stay together in non-standard levels. When the host loaded a level that isn't one of the normal story chapters — such as a developer/debug level opened from the dev menu — other players could be left behind on a different map. The follow-the-host logic now covers these levels too.
• Reviving a downed teammate is more forgiving. The Hold [E] prompt now appears as soon as you are in range (from a slightly larger distance), and briefly releasing the key — or tapping it — no longer resets the progress to zero, so the revive fills up reliably.

New:

• Shared damage numbers on the practice target dummy. Damage dealt to the ChurchHub target dummy now shows its flying numbers and running total to every player, including hits dealt by other players.

Polish:

• Dropped items now glide smoothly into their resting spot for other players instead of snapping into place.

1.1.0 — SULFUR 0.18.3 support, shared loot, and fixes

This update makes SULFUR Together compatible with SULFUR 0.18.3 (Qiosk's Plenty), adds optional shared world loot, and fixes several multiplayer problems. All players must update to the same version before joining the same session.

New:

• Shared world loot (optional, chosen by the host). Turn on Shared loot on the connect page and enemy, crate, chest, and hatbox/register loot is shared — the host rolls it and the first player to grab each item takes it. Off by default (each player keeps their own loot, as before).
• Developer mode is now host-gated. It is a session setting that only turns on when every player has dev access or a session vote passes, so a single player can no longer force it on for everyone. — https://github.com/ryuka-dev/SULFUR-Together/issues/8
• Inter-chunk doors are synced. The hold-to-open doors added in SULFUR 0.18 now open for everyone when one player opens them.
• Thrown knives are visible to other players — you can see the knife fly and stick. — https://github.com/ryuka-dev/SULFUR-Together/issues/10
• External mod channel. A public API so other mods can send data over the co-op session and read basic session info.

Fixed:

• Updated for SULFUR 0.18.3 (Qiosk's Plenty). Re-bound the damage/hit chain, fixed a host-side enemy-AI freeze, and reconnected hooks the update renamed — combat, enemy deaths, and the client→host hit path work again on the new game version.
• Dropped items could become permanently un-collectable for everyone — fixed. — https://github.com/ryuka-dev/SULFUR-Together/issues/11
• Dropped items now rest in the same place for everyone and no longer pile into an indistinguishable tower.

Known issues:

• With shared loot on, the food/material hatbox and cash-register open animations do not replay on other players' screens (the loot itself is correct and shared). — https://github.com/ryuka-dev/SULFUR-Together/issues/14
• The 1.0.0 beta known issues below still apply (occasional enemy snapping, boss desyncs when a client loads ahead, unsynced blood/particles/sounds, 4+ players untested).

1.0.1 - Bugfix update

This update fixes several multiplayer sync problems found in the first public beta. All players must update to the same version before joining the same session.

Fixed:

• Fixed client poison/fire ground hazards causing excessive duplicate damage.
• Synced throwable landing effects such as poison, fire, and explosions across peers.
• Synced in-flight throwable visuals so other players can see where grenades and flasks are thrown.
• Fixed client weapon XP not being credited on kills.
• Fixed one-shot trigger spawns creating separate local encounters for each player.
• Fixed goblin civilians briefly playing spearman attack animations on clients.

1.0.0 — Version 1.0, Public Beta

First public Beta of SULFUR Together, a co-op multiplayer mod for SULFUR.

This is a public test build. The core loop works end-to-end, but many systems are still being polished — expect rough edges. Every player must run the same version of SULFUR and of SULFUR Together.

New since the early preview:

• In-game connect menu — set up and join sessions from Options → SULFUR Together. No more editing config files.
• Steam connectivity — invite friends / join by Steam ID, no port forwarding needed (works alongside Direct IP).
• Direct IP — host shows its LAN address; clients join with address + port + key.
• 14-language localization for all on-screen text (via SULFUR Native UI Lib).
• Friendly fire as a host-authoritative session setting.
• End-of-run stats cards on the return-to-hub screen.
• Join / leave toasts and a live player list.

Working:

• Host-authoritative networked sessions over LiteNetLib.
• Synced level generation / seeds and scene transitions.
• Remote player proxies, held weapons, and projectiles.
• Enemy state mirroring; host-authoritative enemy damage, deaths, and ranged attacks.
• Downed / revive / death co-op flow with an on-screen rescue prompt.
• Boss-encounter authority for several bosses (Cousin, Witch, Lucia, Desert boss, …).
• Synced destructibles and world item drops.
• Independent per-player character, inventory, equipment, progression, and save.
• No-pause multiplayer (the world keeps running while menus are open).

Known issues:

• Clients that load a boss level ahead of the host can desync (e.g. Cousin "infinite dialogue").
• Some enemies may briefly snap, teleport, or animate incorrectly.
• Bosses beyond the tested set may have gameplay-affecting sync problems.
• Blood, particles, sounds, and some animations are not always synchronized.
• Sessions with 4+ players are untested; 2 players is the most predictable.

Dependencies: BepInEx 5, SULFUR Native UI Lib 0.10.1 (both installed automatically through Thunderstore / Gale).

⚠️ Public Beta — expect bugs. Back up your saves. Report issues on GitHub (not Thunderstore, which has no bug tracker). Host and all clients must run the same mod version.