Older than old school, more basic than binary, and still surprisingly good fun!
The solution was to strip the Sonic formula to the bare essentials. Unfortunately this seemed to mean approximately one enemy every 30 seconds or so, almost no detail to the backgrounds and sound effects that make you assume that Sega figured three different ones will do for the whole game.
However, this wasn't all bad: to get around the speed issues and lack of enemies, this game was made much more of a platformer than its Genesis counterparts. In fact, it arguably owed more of a debt to Super Mario Bros. due to the move and jump formula. The zones are all unique enough to distinguish them from eachother and aren't carbon copies of those in previous Genesis games.
Added to that, the "music" for each level is very good, it's very catchy with the Jungle zone being a real highlight. Bonus levels and secrets are basic but fun all the same.
It doesn't look good now, but playing it reminds you of how much fun it was when you were 8 years old, and that youthful enjoyment is only ever going to be a good thing. It's a short game, but it's a fun game, and if that's good enough for Call of Duty 4, it's good enough for this!