A Little to the Left Archipelago

An Archipelago multiworld randomizer for A Little to the Left (Steam, Windows).

Your run is a track of puzzles, many of them procedurally generated. Its solutions, the groups you tidy and the credits are checks; Puzzle Packs, the game's mechanics (Stacking, Rotating, Drawer and the rest), Skips and Hint Pages are items, and any player in the multiworld can be the one holding yours.

You also need

• A multiworld to join. Whoever generates the seed needs alttl.apworld, and every player a yaml; both are on the GitHub releases page. Use the release with the same version as this mod.
• The base game on Steam. Both DLCs are supported and off by default.

Install

1. In r2modman or Thunderstore Mod Manager, choose A Little to the Left and select or create a profile.
2. Install this mod (Install with Mod Manager above, or search the Online tab for A Little to the Left Archipelago and press Download). BepInEx comes with it as a dependency.
3. Press Start modded. The first launch is slow while BepInEx generates its files. The main menu gains an Archipelago entry.

The mod manager shows the version it installed: take the alttl.apworld and yaml from the GitHub release with that same version.

Connect

The main menu gains an Archipelago entry. Fill in the server (host:port from the room page), your slot name exactly as in your yaml, and the password if the room has one, then press Connect. With Auto-connect on, the game rejoins your multiworld every launch.

A randomized run keeps its own save: your campaign save is never written to.

More

• Full guide, options and changelog: github.com/drohack/alttl-archipelago
• Bugs and questions: GitHub issues, or the game's channel in the Archipelago Discord.

Vibe coded with AI: this mod is written with an AI coding assistant (Claude Code).

Changelog

This release's changes. Every release, with how each change was checked: CHANGELOG.md.

1.0.2 - 2026-10-21

The rest of 1.0.1's cleanup and two safety fixes; nothing changes in play.

1.0.1 seeds: finish them on 1.0.1, or regenerate. No location id moved, but the mod refuses a seed made by a different apworld version, as it has since 0.3.3.

Measured, not assumed: the release gate on 1.0.0 and on 1.0.2, same seed, once with cat traps off and once with them on, sent the same 43 checks in the same order, received the same 53 items and logged the same 13 cat-trap outcomes. The seed's spoiler is identical. Not re-run, as nothing they cover changed: the by-hand solve of the levels the gate cannot force, and the level table against the game (levels.json, abilities.json and names.json untouched).

• A save redirect that fails now ends the run. The mod logged "disconnecting to protect the campaign save" and then did not disconnect, so every later save in that run went to the campaign save. It now disconnects on the next frame; the one save already in progress still lands in the campaign file. Never seen in play.
• The connection pane no longer leaves objects behind. Each open left the dialog's body, the game's copy of it and its holder in the scene; the next open now destroys them. The auto-connect pills bind to the copy on screen, as the text fields already did.
• slot_data drops three keys the mod no longer reads: cat_trap_chance (the option still sizes the trap pool) and each slot's source and dlc. The apworld's checks that a slot needs no DLC the seed did not enable now read the level data.
• Smaller cleanups in the shipped DLLs: unused fields, parameters and defaults, two Core members only tests read (SlotEntry.Source, IsGenerator) and SkipReturn.Done are gone; members only their own class uses are private; the plugin build drops five game references and AllowUnsafeBlocks it never needed; stale comments are corrected.
• DevTools no longer references ModKit or ships its own copy of ALTTLModKit.dll.
• The release gate answers a prompt that appears after its post-load look. Colour Assist on Spice Jars could go up a frame later, and the puzzle was then solved under it, which swallowed the retry panel the arrow check needs. --steady no longer says cat traps make a run unrepeatable: they sit at fixed locations, and traps-on runs repeat too.