Metroid: Other M: This game ruined the characterizations of Samus and Adam Malkovich along with contradicting so much of the Metroid lore and the timeline in the poorly written and simple story that even going on six years after it's release, the scar of this on the Metroid fandom has never healed and likely won't for a while.
Sid Meirs: Beyond Earth: While this game had a lot riding on it since it's the unofficial spiritual successor to one of the best Sid Meirs games ever in Sid Meirs Alpha Centauri, but to only turn up to be some 50 dollar mod of Sid Meirs Civ V is just insulting to all fans of Sid Meir alike.
Sonic 06 and Sonic Boom: Rise of Lyric. They both equally deserve the title of worse sonic games for different reasons.
Sonic 06 for being glitchy and terrible loading times, convoluted storyline, and a horrid princess protagonist that promoted both necrophilia and bestiality (you thought Bella was the first?).
Sonic Boom: Rise of Lyric for being so bland and boring in gameplay that frankly it's a boring platforming game with Sonic characters than a Sonic Game. Terrible and unfunny dialogue also weigh it down heavily as well.
COD Ghosts: You think playing Ghosts on a console was bad, try playing it on a PC where your FOV is set so low that my dad nearly threw up for the motion sickness he received playing it because the FOV was set for a big screen TV rather than for a much smaller monitor. To make matters worse, Infinity Wards refusal to fix it till later, a bland and tired story and multiplayer leaves plenty of reason why COD jumped to a near future setting started by Treyarch with BO2.
Star Wars Prequel Trilogy: The amount of lore that it wrecked because it wanted to make Anakin into a Jedi version of jesus is plenty evidenced in Mr. Plinketts vids.
Star Trek V: Final Frontier: William Shatner turns his character into a mary sue while shitting on everything on the franchise. Alot of people don't realize just how bad this film is and how it almost destroyed the Star Trek franchise. To know more, check SFDebris's review on it.
MLP 3.5 Generation: When the official animation is making Dusk's Dawn look good, you have plenty of problems to say the least.
Paper Mario Sticker Stars: When you remove alot of the stuff that made Paper Mario famed (RPG combat and leveling up), you also have tons of reasons why this is the worst in the franchise bar none.
Doom movie: Or as I like to call it, Resident Evil on Mars for turning the whole Doom plot from a demonic invasion and you the lone surviving marine must find better weapons to survive and wade through the unimaginable horrors to a squad based action flick with the demons being turned into super mutants experiment gone wrong.