Better version of Sonic 1 with added screen space, consistent 60fps, smooth rotation effects, Spin-Dash, many fixes to the game's collision issues and bugs, and extras like Tails, Knuckles, Super Sonic and Sonic 3&K power-ups. Made by part of the same team that worked on Sonic Mania, uses older version of the Sonic Mania engine. If you can play with a controller, I highly recommend it. Touch controls take a lot of getting used to, but it works perfectly when you do. I can play this game on touch nowadays as perfectly as I can on controller.