To play Jamjam, use your mouse to aim and click to make the jelly character jump on a PC, or tap on mobile devices to control jumps. Navigate through levels by timing jumps to avoid obstacles and collect coins and stars. Hold the mouse button or press longer to adjust jump height for precision. Access the in-game menu to unlock cosmetic upgrades for your jelly hero using collected coins. Strategize to tackle boss stages by learning their patterns. The game supports fullscreen mode and is playable on browsers or mobile devices via the CrazyGames app. Plan jumps carefully to progress efficiently.