
For all of this fan game's history and reputation, I still didn't expect to like it as much as I do. It's a Sonic game made in the Doom Legacy engine; its control scheme demands direct control of movement and camera, which feels pretty bizarre for a platformer; it replicates the Genesis era's slippery acceleration in 3D. It seems like it shouldn't work.
But something about it clicks for me. After installing Jeck Jims' 3D Models (which feel more consistent with the world than 2D sprites to my eye), it really feels like a 32-bit "missing link" between Sonic 3 & Knuckles and Sonic Adventure.

As bizarre as the game's controls and acceleration feel at first, they're critical for traversing each zone... which are enormous, at least compared to most 3-D Sonic games. This scale serves two functions: To provide adequate room for the series' characteristic speed without the need for "on rails" sections, and to provide the sort of branching paths more common to 2-D entries.
The problem with adding an extra dimension to that classic Genesis style of play is an increase in complexity and difficulty, but that's where the game's multiple playable characters come in. I struggled in the game's second half as Sonic, who's well suited for speedrunning and boss battles but challenging when it comes to avoiding hazards. Switching to Tails allowed me to fly over most obstacles and gain a better sense of the levels as a whole, something that made me better at the game overall.
If you aren't already a fan of Sonic, this game's incredibly unlikely to win you over. You probably won't be as charmed as I was by the special stages (which borrow mechanics from another Sega franchise) or as forgiving of the bottomless pits that plague later levels (among other miscellaneous frustrations). But if you share my odd fascination with Sonic R, Sonic Jam's Sonic World, Sonic Mania's special stages and/or the canceled Sonic X-treme, give this a try! You certainly can't beat the price.