The two worst games that stand out for me were:

Battlecruiser 3000, at least it was free and even at that it was a price too high, never ever got the thing to run.

X-Rebirth (Stillbirth?) It's one redeeming feature was the nice music.

Chlanna nan con thigibh a so's gheibh sibh feoil
Sons of the hound come here and get flesh
Clan Cameron