Worst game for me? Hands down Rifts. Any system where you can't use pilot your fancy Mech because you didn't get the "typing" prereq for computer use (which is a prereq for pilot Mech) is a bad idea to start with. Just how retro is your Mech that it needs a keyboard? What's next? Do you boot it with a 5.25" floppy disk?

And then the issue with their "expansions". Each new expansion made the previous one useless.