It's a competent port of the original Sonic the Hedgehog, though it's a little odd having the Sonic 3 & Knuckles OST slapped on top of Sonic 2 levels.

The screen space gets a bit troublesome towards the end, with the sky fortress level, in particular, causing a number of deaths and increased frustration. Overall though it looks decent and reminds me of the original Master System / Game Gear ports.