This is pretty much exactly what I'd want out of a 2D platformer - good-feeling controls, fun levels (and even good bosses, which are a rarity in the genre), a banger soundtrack, and very high replayability.

The game wears its Sonic inspirations on its sleeve, which on top of being a PC game released in the mid-2010s means it ends up paralleling fellow Sonic clone Freedom Planet. The two compare and contrast in a lot of interesting ways, with Freedom Planet resembling Satam and the Archie comics in tone while Spark reminds me more of the Adventure/Advance games and certain action-y Newgrounds animations. Both are worth your time of course and would get a full recommendation from me to any Sonic fan, but of the two I find myself more likely to replay Spark due to its touch-and-go intro and more speed-friendly levels