Welcome to the next level!

This is a port of the original Sonic the Hedgehog (revision 1, mostly) to the Sega Mega CD (running in Mode 2/off a CD). Not a mere one-zone demo, not affected by an original hack's mechanics, not buried within a joke hack. This is a full playable Sonic game running on the Mega CD, with the source fully available, and with the intent of enhancing the game with the extra hardware.

I started this project about a month and a half ago to present to the contest after another project intended to be shown here was put on hold. (Maybe next year, eh...?) This was done as both a learning experience for myself to learn new hardware (I was already familiar with programming for Mega Drive, but wanted to explore its addons), and as an example others can learn from.

This has been tested with BlastEm, Fusion, Gens, and on real hardware using a Mega Everdrive Pro.

Features:

• Expanded Sound.
• The Mega CD comes with a chip supporting PCM playback for up to 8 channels, complementing the 10 sound channels already in the Mega Drive. This port leverages that by moving playback of drum samples to a custom PCM sound driver running on the Mega CD CPU.
• Because drums no longer need to play on the Mega Drive hardware, an extra sound channel was added in the main sound driver to allow for more sound effects to play without cutting out channels of the music.
• Unfortunately, I was not able to get CD audio playback fully implemented in time for the initial release. Most of the pieces are there though, and I intend to add it in a future update.
• An open-source Mega CD game. The scene for Mega CD has grown significantly over time, and over the years there has been new homebrew and hacks of other games, but not nearly as much done with the blue guy this contest is about. This port aims to change that; this is a full game running on Mega CD, with source code and development history available for browsing right now. Code for the kernel programs to load and run the game from disk is written in mostly C using the megadev toolchain. Rom hackers and developers more familiar with the Mega Drive standalone can use the code repository as an example of how to bring more full-fledged MD projects over to Mega CD with as few changes as possible.
• Other features:
• Custom loading screen while files are loaded from CD
• Modified title screen, to remind you that this is indeed utilizing Mega CD hardware
• Various bugfixes applied (for those familiar with Sonic Retro's Sonic 1 disassembly, FixBugs is turned on)
• Much smoother special stage. The movement of objects making up the maze was unlocked, and the walls now display with 128 degrees of rotation (up from 16).

Even though I started this project to have something for SHC, I'm incredibly happy with what's been done so far, and I intend to work on it further after the contest to add more features. I consider this the beginning of a goodbright future for Sonic games and hacks on Mega CD.

Note: Debug mode and sound test have not been fixed to accommodate for the code has been moved around. Try at your own risk! There is also a small instrument issue at the beginning of the credits music that quickly corrects itself; otherwise, the music plays perfectly.