Crackdown
Orb Hunter - If you notice, I got it almost a YEAR after I did pretty much everything else in the game and that's after getting stuck at 499/500 on my first gamertag once before. They really should do like Burnout Paradise and tell you in which section of the city you are missing an orb. At least then you could narrow your search. Luckily for me when I went searching the other day I picked the right island off the bat (Shai-gen).
Call of Duty 2
Veteran - It's worse than Veteran on COD4, it's more annoying than Mile High Club. I freaking hate monster closet Nazis.
The Outfit
Prisoner of War & Victories Keep Piling Up - They're not really hard but I mean, come on, 500 wins AND 200 loses? Boosting it is taking forever with my friend. Imagine how bad it is legit.
E4
Master of the Extreme - Forget that you can't get hit once or your multiplier will reset, how about the fact that it will take almost 2 hours of continuous play to even have a shot at the achievement?
Kingdom Under Fire
Marguerite, My Love - Probably the most soul-crushing achievement I've actually bothered to get. It's so boring and so random, it's just the worst.
Streets of Rage 2
High Score - Way to make my favorite Genesis game a thorn in my ass, Sega. That fat, bald boxer at the end of Stage 5 can shaq-fu himself.
Puzzle Fighter HD
Chain of Jewels - There is little skill involved, just the luck of the draw as to if you get a lot of bomb orbs early on or not.
Mad Tracks
Ultra Fast Food - Again, a lot of luck is involved as you'll need almost non-stop boosting to get it and I never get that many boosts in a row.