Since many older players here and we talked about it on vent, here some nice retros playable in browser:
Defender of the Crown:
http://www.cinemaware.com/browser/dotc/final.asp
Dr.Mario
http://nintendo8.com/game/495/dr._mario/
Sonic The Hedgehog
http://mastersystem8.com/game/513/sonic_the_hedgehog/
Indiana Jones and the Last Crusade
http://dosdose.com/game/152/indiana_jon ... t_crusade/
Pirates!
http://dosdose.com/game/746/pirates!/
Winter Games
http://dosdose.com/game/725/winter_games/
Lemmings 2
http://dosdose.com/game/272/lemmings_2_-_the_tribes/
Sierra Games - SpaceQuest, Policequest, Larry
http://sarien.net/