After seeing some reviews, I am honestly beginning to theorize a certain Sonic game began development as a simple slow-paced platformer that was unrelated to the franchise, with the only protagonist being a customizable character. Then the creators for some reason thought it should be a Sonic title, so they shoehorned in Sonic characters and locales.
Story:
There was originally a decently written storyline when the game began development, that has been given plot holes when the Sonic universe was introduced that gradually became worse as more parts of the game’s plot were given adjustments during development. They needed to turn Sonic into the lead protagonist, so they had to adjust the plot to accommodate the fact there is now also multiple protagonists in the game, and turned the customizable character into a sidekick. But they still wanted preserve most of the plot, so they tried making slight re-writes to parts of it multiple times in an attempt to make it fit within the Sonic universe, neglecting the continuity of both itself and the Sonic franchise in general.
Gameplay:
The normal boost gauge was originally used only for ammunition. The weapons originally weren’t based on wisps, and each had two different magical properties that are each refilled under different conditions. To give the gameplay a faster pace, they decided to cut the ammunition idea entirely and tried to make the avatar’s top speed faster. They never changed enough of the level design to work with fast paced gameplay, resulting in some very short levels. “Double boost” was originally a generic temporary power-up (whatever it was) that was turned into automated hallway sections after the regular boost made it redundant, with the gauge originally being a simple timer. Classic Sonic was originally meant to be “wisponless avatar”, where the avatar only had a grappling hook to assist them.
Conclusion:
I think what actually happened was that they tried to combine and preserve two clashing concepts and it resulted in a huge mess of a game. However, there is also a chance it could just be coincidence. However, I’m also sure this game would have been even more bland if it wasn’t a Sonic game.
(I am sure I may have missed a few things when writing this…)