The SEGA Megadrive (aka SEGA Genesis) released in Japan in 1988 and Europe in 1990 was a very fine games machine in its day. Games like Sonic the Hedgehog stand up today as great entertainment.
Accessibility wise, the Megadrive benefited from a fairly large range of controllers, including a number of fully compatible arcade sticks and the "Action Replay" cheat cartridge. All of this and more is possible through emulation.
To play the games listed below on a modern PC you will need to use a SEGA Megadrive Emulator such as "GENS" alongside game files (aka ROM images) for each game. You will likely need to keep a separate record of what keys are needed as well as taking notes from each game's instruction manual.
The GENS emulator is a great place to experiment with 4Noah utilities for reducing controls if needed as well as JoyToKey if you are using a joystick compatible controller. See the Accessible Gaming Utilities for direct links.
You can discover many more games at Video Game Critic and can pick up "SEGA Mega Drive Ultimate Collection" to play on Xbox 360 or PS3 albeit with less accessibility options than through PC emulation.
Columns is a one or two "match 3" puzzle game.
Essential controls are LEFT, RIGHT and "A" (plus ENTER to begin). Could work out as an ideal team game where controls are shared.
Accessibility Utilities: Speed control utility CPU Killer can slow gameplay down to make play much easier.
Flicky is a one player arcade game.
Essential controls are LEFT, RIGHT and "A" (plus ENTER to begin). Again this could work out as an ideal team game where controls are shared.
Accessibility Utilities: Speed control utility CPU Killer can slow gameplay down to make play much easier.
Atari coin-op conversion Marble Madness for one or two players.
A fine conversion of an arcade classic. Used in the past entirely with muscle sensors.
Sonic Spinball for one to four players.
Requires the use of the cursors and the "D" key (plus ENTER to begin). Team play potential where the one-switch gamer could take control of "D".
Accessibility Utilities: Speed control utility CPU Killer can slow gameplay down to make play much easier.
Sonic the Hedgehog for one-player.
Essential controls are LEFT, RIGHT and "A" (plus ENTER to begin).
Accessibility Utilities: Speed control utility CPU Killer can slow gameplay down to make play much easier. 4Noah can be used to reduce LEFT and RIGHT down to one-switch.
Streets of Rage II scrolling beat-em-up for one or two players.
Play is possible with the cursors and "S" key (plus START to begin). Team play for one-switch gamers quite possible, but requiring many presses.
Accessibility Utilities: Speed control utility CPU Killer can slow gameplay down to make play much easier. 4Noah can be used to reduce LEFT and RIGHT down to one-switch.
LEGAL NOTICE: Many game ROMs remain the copyright of the original owners who may or may not be happy for them to be played under emulation. Put in the context of these games impossible to play in their original format for some disabled gamers and I would hope that attitudes would be more relaxed. Support developers by letting them know why you can't play their games and offer some solutions.