This is pure "Sonic Porn" as Cory Beck would put it

The momentum and speed you can achieve in this outclasses Sonic generations, the amount of options you get for total control is fantastic. There is no hand holding, you have total control over your movement and it feels great. Enough tools in your kit to blast around at crazy speed, but nothing too wild that you can skip entire level segments normally. Fast enough to get the rush of adrenaline but steady enough that you can make decision on the pathways you want to take. It's nearly impossible to find a 'best' route, you find more and more shortcuts each time you play.

As great as the platforming is, the combat/driving/mecha segments feel out of place personally, but I understand that Spark and most Sonic-inspired fan games have an element of combat added and have been for years, so even if it's not my cup of tea, it doesn't really take away from the whole experience. They are small mini-games that shake up the gameplay, it's acceptable.

EDIT: I take it back, the combat is great, I sucked at it. Get the Finger Shot and Combo Shots.

tl;dr
Platforming God Like, Combat decent, Buy it and feel like a pro speed runner in minutes!