Sonic VS Robotnik

• physical : no
• rom : yes
• genre : Action > Platformer
• licensing : unlicensed
• code : sonicvsrobotnik
• Date(s) : 2026-wip
• Platform(s) : MD
• By(s) : cpc

Data retrieved from jph

Sonic VS Robotnik

• title : Sonic VS Robotnik"
• last updated : 03 September 2026
• genre : Action > Platformer
• by : cpc
• hack type : Co-op / Multiplayer
• download : 31
• platform : Sega Genesis
• code : sonicvsrobotnik

/home/jph/Documents/md-pages/Romhacking.net - Hacks - Sonic VS Robotnik.html

This is a hack which turns the boss fights of the original Sonic the Hedgehog for Genesis/Mega Drive into a local 2-player duel. Player 1 is Sonic. Player 2 controls Robotnik and fights back.

The game boots straight to a duel picker. Choose a fight with the D-pad and press jump or Start to begin. Each round Sonic has 1 ring and 1 life: Robotnik wins if Sonic dies, Sonic wins if he beats the boss, and either result drops back to the picker. Either player can pause with Start. Robotnik reads the second controller, so a pad must be plugged into port 2.

The duels:

Green Hill: the wrecking ball
Marble Zone: the flamethrower
Spring Yard: Robotnik smashes the floor blocks
Star Light: the seesaw spike ball
Swiss Army Knife: a bonus “super” Robotnik with every weapon plus an orbiting spiked ball, over Special Stage music

The fights are deliberately asymmetric. The two sides don’t play the same, and some duels favour one player.

This has been tested on real Mega Drive hardware. The patch applies to the Sonic the Hedgehog (USA, Europe) Rev 00 ROM in BIN format (CRC32 F9394E97, the standard No-Intro dump). It has not been tested on other revisions. The patch is in BPS format, which checks your ROM before patching, so a wrong ROM is rejected rather than mispatched.

Version 1.0

First release: five duels.

Screenshots