Merge 13

Numbers replace colors as the thing you're matching here: draw a line between circles that share the same number, and they merge and clear from the board. Chaining several matching circles together in one move scores more than picking them off one at a time, so there's a real incentive to scan the whole board before committing to a line rather than grabbing the nearest obvious pair. It plays faster than most match-3 games since there's no swapping pieces around first — you just connect what's already there and move on. A decent option if you like puzzle games with a numerical hook instead of the usual fruit or gem icons, and simple enough to pick apart within the first couple of rounds.