If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
Play free online Sonic Jigsaw game at Cartoon Games. Drag the pieces into right position using mouse. Multiple pieces can be selected using Ctrl + Left Click. You can choose one of four modes: easy, medium, hard and expert. But watch out on time, if it runs out you will lose! In any case you can disable the time, and play relaxed. Click Shuffle and start the game.