Project Spikepig
About
Project Spikepig is a Sonic fangame I've developed from 2009 to 2017, at first in response to Sonic 4 like so many others.
The current build of the game features Sonic, Tails and Knuckles and several finished zones, including beta versions of Tropical Trance and Shiver Square. The last one to be developed was Parabolic Pachinko. Levels such as an abandoned amusement park, a desert level with Fang as a boss (Playable/Boss Fang basically was always among a fangamer's Holy Grails) and the two last zones after Cobalt Capital (a second fortress level mixed with ruins and the crystalized core of the planet) never went past the drawing board, unfortunately.
The source file is also available for the curious who have Multimedia Fusion 2 or Clickteam Fusion 2.5, but do note that it was developed in a Beta build of Sonic Worlds. Look up the current version of Sonic Worlds Delta or Simple Sonic Worlds if you want to give development of momentum-based platforming a try.