MNEMOS — Rewind the room and solve it beside your own ghost

What is MNEMOS — Rewind the room and solve it beside your own ghost

MNEMOS is a real-time puzzle-adventure on a nineteen-by-thirteen grid of buried stone. You are a Cartographer descending through a machine somebody sealed on purpose, and the machine's one gift is Recall: press it and the chamber snaps back to the second you entered, while everything you just did keeps happening as a glowing Echo of yourself. The Echo is solid to the world and transparent to you. It stands on pressure plates, blocks light beams, shoves crates and pulls a warden off your back, and it lives exactly as long as the loop you recorded. Nothing pauses while you think it over.

Twelve chambers run in three acts, from the Shallow Archive to the Core. Each hands you a fixed budget — one to four Echoes, seventeen to twenty-eight seconds of loop — and every lock is arithmetic you cannot do alone: two plates, one body. Crystals wake only to lantern-light or a beam, and the Gate stays shut until all of them burn. Dying costs nothing but time, because the Echoes you have woven and the shards you took survive it. Stars reward restraint rather than speed. After chambers four and eight the machine offers an attunement, and progress saves chamber by chamber.

How to play

1. Move with WASD or the arrow keys, or the left half of a touch screen, and press E or Space to lift a lantern, put it down, or throw a lever.
2. Press R to Recall: the chamber resets and everything you did that loop replays as an Echo, holding a plate or blocking a beam while you work elsewhere.
3. Press Q to collapse the loop when a plan has failed. Room and Echoes reset and it costs nothing, unlike a Recall, which spends one of the chamber's Echoes.
4. Wake every crystal with a lantern or a beam, then walk into the Gate. Finish inside the Cartographer's par and the chamber seals behind you with three stars.

Strategies that work

• An Echo lives exactly as long as the loop you recorded, so seconds spent standing still before a Recall are seconds it will stand still later. In Chamber 8 it must shove a crate clear, reach the plate and hold it while you cross half the map: wait three quiet seconds there first.
• The cracked planks in Chamber 7 take one crossing from you and none at all from an Echo, because the floor only reacts to your own body. Send the Echo back to the plate on the left, spend your single crossing on the run to the Gate, and never turn round for the shard.
• A crate holds a plate down as well as a body does and, unlike an Echo, it never expires. Chamber 3 starts with its crate exactly one tile below the left-hand plate: one shove upwards solves half the lock for good, which is why the par there is one Echo instead of two.
• Wardens read a cone about six tiles long and seventy degrees wide, and need roughly four tenths of a second of unbroken sight to raise the alarm. They cannot tell an Echo from you, so in Chamber 6 walk one loop past the patrol, Recall, and let the decoy clear your corridor.
• Stars measure restraint: three at or under the Cartographer's par, two for one over, one for anything worse. The score agrees. Each Echo spent costs a hundred and ten points and each second costs four, while a shard adds three hundred, so take the shard on your first loop.

A little history

MNEMOS was written for puzzle-me.com and has no older ancestor to claim. It belongs to the small family of puzzles built on self-cooperation: the player records a run, the recording replays as a second actor, and the rooms are shaped so that one body could never finish them. The idea surfaced in a handful of independent games from the late two-thousands onwards, and it sits close to the mathematical notion of a fixed point, a solution that has to contain itself. What MNEMOS adds is scarcity: the loop is short and recordings are currency.

Frequently asked questions