Hard Drivin': My favorite arcade game EVER was also the worst port EVER. Of course, EVERY port of Hard Drivin' sucked! Test Drive II had better physics, for heaven's sake!
(Don't you be slamin' Test Drive II. That game was pure addiction).
Stun Runner: This was also a pretty bad conversion. The arcade version was based on the same arcade hardware as Hard Drivin', so I was naturally biased from the start.. Of course, I soon realized that the arcade version sucked, too, so I shouldn't have expected any more from the home version.
Count Duckula: I hate games when you stop moving around, the character looks blankly back at you like they have lost their will to live. Count Dupeula is more like it. Not so much "bad" as "boring". I'm glad I never actually bought this one.
Celica GT Rally: Half the time the damn game wouldn't even boot up on my A1000. Still, I had fun playing it because it was still challenging. But, looking back, I think I was just braindead.
Titus the Fox: Great mascott, crap game. I'm surprised Titus Software is still alive and making more crap games.
All Dogs Go To Heaven: In the category of cartoon lisences, this was the worst. Long load times were accompanied by pointless "dodge the bad guy" anticts. The programming was so bad, the characters flickered like crazy as they "moved" across the screen. Truly awful.
Second place awarded to Oliver and Company. Pioneers in animation produce flickering frames on the computer. Both Bluth and Disney did crap edutainment, even before the industry really took off on the PC or Mac. Ouch.