Reset zoom and inspect the viewport
If the page is zoomed in, use the browser’s reset or default zoom control so the game can fit its intended area. Then scroll to check whether the game begins below the browser toolbar. A mobile browser can reserve part of the screen for its address and navigation controls, making the visible portion smaller than the full display.
Try Stack or Orbit as a visual check: the moving slab or spark should be visible with enough surrounding space to understand the action. If any portion is cut off, rotate the phone once or return the page to its normal view. Do not pinch while a run is active unless you know the page responds safely.
Reload only when you are ready
Some layout changes take effect after a reload, but reloading can restart the current attempt. If you are in the middle of a run you care about, wait until it ends or choose to abandon it before refreshing. Browser tabs can also retain an old layout after rotation, so closing and reopening the page may help when a simple orientation change does not.
If the problem persists, confirm that the browser is current and try another supported browser if available. Avoid assuming the game is broken based on one setup. Different devices and browsers render pages differently, and a display that works on one phone may not fit another screen in the same way.
Questions about browser game cropped on phone
Can I zoom in to make controls larger?
You can change browser zoom, but zoom may crop or shift the game instead of enlarging controls usefully. Return to default zoom if the play area becomes harder to see.
Will refreshing save my run?
Do not assume an unfinished attempt is saved. A reload can restart the game, so refresh only when you are prepared to begin again.