Tower Builder — free browser game

Tower Builder is a timing-focused browser take on the classic tower-stacking games; your goal is to raise the tallest tower reaching into the sky, block by block. A block slides continuously back and forth across the top of the screen, left to right and right to left; your job is to catch the right moment and press SPACE (or tap the screen on mobile). When you drop the block, the part of the new floor that overlaps the base of the floor below stays in place, while the part hanging over the edge snaps off and falls away — so the later you react, the narrower the next floor becomes. After each successful floor the block slides faster, so the higher you climb the more your reflexes are tested; a small delay means a sharp misalignment instead of a smooth fit. When the block's width drops below a certain threshold the building collapses and the game ends. Your score is the number of floors you build; your highest score is saved in the browser and reappears in your next session even if you close the page. As a strategy tip, the block's speed dips for an instant when it changes direction (at the edges), so pressing during that micro-pause is the easiest; also, each floor should land not in the centre but perfectly aligned with the floor below it, so the tower doesn't narrow. The R key or the 'Restart' button starts a new round; as you practise your rhythm settles in and reaching 30+ floors becomes possible.