Ultimate Flash Sonic

Ultimate Flash Sonic is a 2D platform game, a Flash game created by Dennis-Gid, released on Newgrounds in 2004. It's a remake of the classic Sonic gameplay, allowing players to choose from four initial characters (Sonic, Tails, Knuckles, and Cream), with two secret characters (Amy and Shadow) to unlock. The game features iconic levels, a password system for saving progress, and unlockable features like level select, a jukebox, and cheats.