Screw Puzzle Jim is a sorting puzzle wearing a hardware shop as a costume. Wooden planks are held together by coloured screws, you have a limited number of plates to unscrew them onto, and each plate only accepts one colour.

The catch is that a plank only falls away once every screw holding it is gone, and screws underneath other planks cannot be reached until the planks above them are cleared. So the puzzle is really about order: which screw first, and which one you can afford to leave.

How to play

• Tap a screw to remove it and send it to a matching plate.
• A plate fills up and clears once it holds a full set of one colour.
• Planks fall away when the last screw holding them is removed.
• You lose when every plate is occupied and no screw on the board matches any of them.

The mistake everyone makes first

Filling plates greedily. Sending three colours to three plates in the first few taps looks like progress, but it leaves you with no free plate and a board full of screws in a fourth colour. Finishing one colour completely, so a plate clears and comes back, is almost always better than starting three.

When a level looks impossible, the answer is usually a screw you dismissed as unreachable. Removing a single screw from a plank you were ignoring often drops it and exposes half the board underneath.

Good to know

• Hundreds of levels that build on each other rather than repeating.
• Undo and hints for when a board genuinely locks.
• The unscrewing sound is, we are told, the main reason people keep playing.
• Offline and free.