Ah yes... Either Left 4 Dead on expert is no easy feat and definitely worthy of mention, whether you include the commonly used exploits/glitches to beat them or not.
Not Gonna lie. I found that game to be challenging but not HARD
Hardest game ive beaten?
Contra: Shattered Solider on hard mode,
the AVGN game
Ninja Gaidan 2 on xbox (took me like 6 months to beat it)
the first two metal slugs
KOF 98 on hard mode. Omega rugal is cheap as hell
Yea, and i mention left 4 dead before all of the different exploits were exposed. MY friends and i found most of the shortcuts and and cheats on our own before they became youtube favorites. To this day, if you try and beat L4D without the shortcuts it's still an extremely trying experience because of the AI generator. My friends and i discovered most of the cheats that are now commonly used orhave been patched before they reached the internet. That game remains my favorite game experience of all time.
Another one worth mentioning is, Enslaved. Beating that game on perfect was a frustrating example of trial and error.
__________________ "If you tell the truth, you never have to remember anything" -Twain
(sig by Scythe)
Dark Souls 1.
Completely finishing Sen's Fortress and getting everything in it was murder. The hardest part are all of the traps, and going in there with a high soul level may make you regret it if you lose them all. DS2 was a big let down compared to the first one. Well at least to me it was.