Ver. 0.8: Controls are WASD for movement, the P key for the boost, and O for the stomp. The homing attack is jumping while in the air when enemies are in range, eventually doing this with no enemies in range will result in an air dash. The homing attack does not have a lock on courser yet. Fill up the boost gauge with RINGS! You may choose to switch this to wisp capsules if you wish. Ver. 0.8.2: The air dash has been added, but it's a bit inconsistent for some unknown reason. Ver. 0.8.3: The air dash has been fixed. Coding Instructions: Black=Ground: Trace the traversable sections with black, but make sure that everything else is at most a very dark shade of grey to avoid any blockage or traversing of non-ground. White=Movement Correction: Pushes character up or down to avoid clipping through floors or randomly falling when running through a level. Turn ghost effect to 100 to have the effects of the sprites remain but also make their appearance scarce. Homing attack: New lines of code in sonic's sprite need to be made for each homing attack. Momentum: Make sure there is enough of flat ground before inclines, as you need to build up speed to travel up hills.
I used Sonic Forces and fan-made Sonic Colors assets from google images. Everything else besides the base scrolling mechanics are my own designs and ideas. The unfinished building model is based of the first building to the left in Modern Sonic's level: City heights, assumed to be the first act of two, as we have seen screenshots of city heights that haven't been represented in gameplay footage.