UndertaleArchipelago randomizer mod

Playing with others

Each slot runs its own Undertale adventure. Optional visibility of other players is not shared-save co-op; items and optional deaths are exchanged through Archipelago.

Known scope and limitations

• Use your own Windows Steam copy, even on Linux, where the guide uses Proton or Wine. /auto_patch makes a separate playable copy under the Archipelago user directory; back up saves before setup.
• Version 0.6.8 fixes the omitted-path case, but the patcher does not verify the original data.win hash. If patching fails, restore a clean game copy instead of repeatedly patching an already modified file.
• On Linux, configure /savepath before connecting. Keep this folder dedicated to the intended run: connection cleanup deletes item, check and victory communication files, without a game-side seed/slot check.
• Keep the client connected while receiving items or completing a route. Interrupted checks and victory files are not durably retained through every disconnect; /resync cannot establish full recovery on its own.
• Progressive weapon/armor handling restarts its counter for each receipt packet. Use ordinary equipment settings if you want to avoid that identified progression limit.
• The packaged Linux World and Python client match the reviewed source. The game modification is a binary patch without corresponding editable sources, so game-side effects and compatibility remain partly unverified. No game session was performed.