Sonic the Hedgehog 2 is a 1992 platform game developed and published by Sega for the Sega Genesis. It follows Sonic as he attempts to stop Doctor Robotnik from stealing the Chaos Emeralds to power his space station, the Death Egg. You can save your data to your browser. Click the settings icon and press "Save State Location", then change it to "Keep in Browser". You can enter fullscreen by hovering over the game and pressing the fullscreen button in the bottom right If pressing enter causes the game to tab in and out, just click on the middle of the game to refocus.