Drop the sliding block with a tap, click, or Space. Land it dead-centre for a perfect — full width, rising combo. Miss and the overhang slices off; the tower narrows and speeds up. From height 8 the swing drifts, so read ahead. Width zero ends the run. M mutes.
How to play Stackline
A block slides back and forth above the tower. Drop it with a tap, a click, or Space. Land it dead-centre for a perfect — you keep full width and build a rising combo. Miss and the overhang slices off, so the tower narrows and speeds up with every sloppy drop.
From height 8 the swing starts to drift sideways, so you have to read the motion ahead instead of reacting to it. There are no lives and no timer — the run ends the moment your width hits zero.
Tips & strategy
- Chase perfects early; every clean drop keeps your margin wide for the hard heights.
- Above height 8, account for the drift — release before the block reaches centre.
- A perfect snaps back to full width, so one clean drop resets your room for error.
- Watch the block, not the tower; the swing speed is your real clock.
Stackline is a free one-button stacking game online with no download — time each drop, read the drift, and chase the tower height right in your browser.