Best: CD-ROM
Though the load times kinda sucked, the extra storage space allowed for a lot of things that were difficult to impossible to replicate on a cartridge. I don't know if I'd call this a "PS gimmick" though as the PS1 was far from the first console to use CDs, just the most successful.
Worst: PS Portal
Sounds like a cool idea on paper, but in practise the lag can make fast paced games a nightmare.







