Apple's Macintosh launched in 1984 and was an instant success, thanks in no small part to the famous "1984" commercial which aired during the Super Bowl two days earlier. While initially a bit of a higher-end computer compared to the Apple II line, Apple began focusing on the Mac family more as time went on, even producing the IIe Card from 1991-95 (making Macs compatible with a large chunk of Apple II software) specifically to help educators transition from Apple II-based classrooms to Mac-based ones.
"Classic" refers to the pre-OS X era, spanning from 1984-2001 (up through Mac OS 9). Here lie games from that dark period, fighters of a desperate battle for relevance with an audience more concerned with Quark than Quake.