Deadbolt

Slide the blocking pieces out of the way so the target piece can reach the exit on the right-hand edge. Horizontal pieces only move left and right, vertical ones only up and down — and on top of that each level layers on constraints that make most pieces less free than they look.

• Fuel: a piece has a budget for how many single-cell steps it may ever make. Spend it and that piece is stuck where it stands.
• Rails: some pieces are one-way and can only ever slide in a single direction. Reversing is illegal, not merely costly.
• Locks: a locked piece cannot move at all until some other piece is parked on the switch it is keyed to.
• So a piece parked on a switch is doing a job, and moving it off undoes that job.
• You win when the target piece reaches the exit cell.

• Desktop: click a piece to select it, then use the Arrow keys to slide it; or click to nudge
• Phone & tablet: tap a piece and tap to slide it, fully touch-driven

• Daily: the same puzzle for everyone each day
• Practice: a fresh layout every run
• Easy, Medium and Hard add bigger grids and tighter fuel

• Read the fuel before you move anything. A piece with three steps of budget is a piece you get to move once or twice, so spending it exploring is how levels become unsolvable.
• One-way pieces are a resource you spend rather than a piece you position. Once it has travelled, that direction is all it has left.
• Work out which piece must sit on the switch before you plan the rest. That piece is effectively furniture for the remainder of the puzzle.
• A level can be made impossible without any warning. Nothing tells you a piece is out of fuel until you try, so plan the whole sequence first.
• Clear the exit row last. Pieces parked there are usually the ones you needed elsewhere.

Deadbolt adds a fuel-budget twist to the sliding-block puzzle, rewarding planning ahead to free the key piece in fewer moves.

• Skills: spatial reasoning, planning, sliding-block puzzles, optimization
• Best for: roughly grades 4–12 (ages 9+)
• For parents & teachers: planning and spatial reasoning under a tight budget.

The layout is Rush Hour — invented by the Japanese puzzle designer Nob Yoshigahara in the 1970s, first sold in the United States in 1996, and manufactured by ThinkFun. Horizontal pieces move only left and right, vertical ones only up and down, and the target piece escapes at the right-hand edge.

The axis lock is the whole idea, and it is what separates Rush Hour from an ordinary sliding-block puzzle: a piece cannot be steered, only shoved along its own line.

This version layers on further constraints that make most pieces less free than they look. That presses on the parent's real difficulty, which is not finding the exit but discovering that the blocking piece must first move away from where you want it.

Deadbolt is an original, free browser game that adds a fuel-budget twist to the classic sliding-block puzzle. It is built in-house and plays in your browser.

A free, original browser game on PlayPendium. No download, no install.