SRB2! - sonic robo blast 2!
in development for 11 years, sequal to a 2d game, planned to have 9 zones + extra levels
srb2 is a 3D open-source Sonic the Hedgehog fangame built using a modified version of the Doom Legacy port of Doom.
and is based on the sega genesis games. and i love it! ^.^
and i think you should try it too! (obviously why else would i post this
)