How to Play Tandem

Tandem is a grid-based puzzle game where you control two holographic avatars at once. Every arrow key (or swipe on mobile) moves both the Cyan twin and the Magenta twin in the same direction simultaneously. If one twin is blocked by a wall, only the other moves — this wall-pinning mechanic is the core of every puzzle solution.

Each twin has a colour-matched goal pad drawn as pulsing corner brackets. A level is solved the moment Cyan stands on a cyan pad and Magenta stands on a magenta pad after the same input — both on the same beat. Translucent white prism crates block the way; either twin pushes one by walking into it, and the crate only shifts if the square directly behind it is clear of walls, crates and the board edge.

Every level uses the same layout contract: Cyan starts at the left wall on the top row with its pad at the right end of that row, and Magenta does the same along the bottom row. Only the walls and crates between the rows differ, and that asymmetry is what lets the pair break lock-step. Cyan always resolves before Magenta, an input both twins are blocked on is discarded without ticking your move counter, and the twins never collide — they share squares and pass straight through.

The campaign runs nineteen hand-built levels, from the empty room of Move together at par 6 to Final sync at par 36. Boards grow from eight columns wide to twelve and the crate count climbs from none to four. There is no timer and no fail state — only your move count and the score it earns.

Tips and Strategy

• Pin one twin to separate the pair. Walking a twin into a wall makes the next input move only the other twin. Use wall-pinning intentionally, then reroute the free twin to its pad without dragging the other.
• Solve the harder twin first. If only one twin has a tight path full of crates, route it onto its pad first. The pads do not need both twins simultaneously until the very last input.
• Compare the two rows first. The puzzle is really about the difference between the rows: squares where one row has a wall and the other does not are the only places the pair can change its relative offset.
• Never push a crate into a wall you still need. A crate only moves away from the twin touching it, so one shoved flat against a wall can never come back along that axis, and one shoved into a corner is frozen for good.
• Watch the pad outline. A goal pad pulses while empty and switches to a solid outline with a rising two-tone chime once its own twin stands on it — your checkpoint before routing the second twin home.
• Undo, never restart. Undo (U or Z) is unlimited and preserves the first-try bonus; restart wipes it, and restarting from the solved panel also un-counts that level's score. Rewind a step at a time instead of resetting.

Controls

• Arrow keys / WASD — move both avatars one square in that direction
• U or Z — undo last move (unlimited)
• R — restart current level
• M — mute / unmute the sound effects
• Swipe on mobile — the longer axis picks the direction; very short drags are ignored, so a stray tap never burns a move
• On-screen D-pad — a four-way pad appears below the board on touch devices during a level
• HUD buttons — Undo, Restart, an SFX toggle and Menu, along the top of the board

Keyboard input is ignored on the title screen, and Menu abandons a campaign run without submitting anything.

Scoring, Par and the Daily Challenge

Every solved level pays a base of 100 points times its level number — 100 for the first, 1,900 for the last — plus three stacking bonuses: +50 for finishing in par moves or fewer (+25 within par × 1.5, rounded up), +30 for no undos, and +20 for no restarts. A perfect level is its base plus 100, and the solved overlay itemises the base and every bonus you earned, so a missing line is the one you dropped.

Restarting from the solved panel rolls that level's score back out of your campaign total before you replay it, and a restart at any point costs the +20 first-try bonus, so undo is nearly always the cheaper repair. The campaign total is submitted once, when you clear the final level and the primary button changes from Next Level to Submit Score. Daily mode instead picks one level using a seed built from the current UTC date and posts to a separate daily board.

What Makes Tandem Different

Most box-pushing puzzles give you one body and ask where the boxes go. Tandem gives you two bodies and a single control stream, so the real question is how you desynchronise something wired to move as one. Walls stop being obstacles and become tools: instead of routing around one, you steer a twin into it, because a blocked twin is a parked twin.

The presentation follows that idea — both avatars leave a fading ghost trail, a push throws a shockwave ring and drops the audio a full octave, and clearing a level expands a ring from each twin until they touch.

A Brief History of Box-Pushing Puzzles

The genre starts with Sokoban, designed by Hiroyuki Imabayashi and published by Thinking Rabbit in 1982. The name is Japanese for "warehouse keeper", and the premise — push crates onto marked squares, never pull — has been reimplemented on nearly every computing platform since. The rules fit in a sentence but the puzzles do not: deciding whether a Sokoban level is solvable at all was later proved PSPACE-complete. Tandem's twist is on the input side — one instruction, two actors.