Move your mouse / drag your finger to slide the bucket. Catch only the gems matching the TARGET swatch — catching the wrong color ends the run. Missing a good gem is fine, just try again.
Prism Catch is a free online color-matching game: gems of every color fall from the top and you must catch only the ones matching the current target color. Missing a good gem costs nothing, but catching a single wrong color ends the run instantly — and the target keeps changing, making sustained focus one of the hardest catching challenges around.