Slow and steady.
I know I'm in the minority on this one, but my favorite classic Sonic stage from the first game is Marble Zone. Why? Because you can't gain speed: it's all precision platforming.
Perhaps this is why I enjoy this Sonic the Hedgehog on Game Gear so much. While it is faster than the average platformer, your time is not spent watching Sonic going through loop-the-loops, but doing more careful, methodical platforming.
The slower pace of the game fits the handheld format well because of the reduced screen real estate: you would have even less time than in a regular Sonic game to react to hazards popping out of nowhere.
The game has its quirks. Fans may be disappointed that the chaos emeralds are simply found in Act 2 of each level instead of won through mini-games. There is never more than one enemy on screen at any time, and slowdown can occur when there are too many rings or moving platforms on screen. But for such an old handheld game, it is very nice to look at and the fidelity of the music is impressive.
Weirdly enough, the game may appeal more to fans of the platformer genre who do not like Sonic games, traditionally. If you have enjoyed 3DS Virtual Console gems like Adventure Island or the Super Mario Land series, definitely check it out.