Nice. I rented and beat Demon's Crest long ago which was the first in the series I played. Beautiful looking art design and graphics in that game, that really stood out for me.
Yeah, I always have a problem getting my party shot up then I have to leave people behind to get treated which leaves me short party members. It is indeed hard to judge cover or if you can even hit the enemy without some sort of accuracy indicator or something.

Here are a few, even though there are much more. Some on my list are worse than hard: they cheat :)
Metal Gear (NES)
TMNT - The one published by Ultra (NES)
Wizards and Warriors (NES)
Ninja Gaiden (NES)
Fester's Quest (NES)
Rambo (NES)
Deadly Towers (NES)
Dragon's Lair (Sega CD)
I played the Genesis version. That game was difficult but fantastic, especially the setting and death animations.

double dragon on the nes
they are all three hard
double dragon 1 turns in to a platformer half way through
double dragon 2 does the same

and double dragon 3 ramps up the difficulty

the megadrive ports of 1 and 2 are arcade ports and off course ramped up the difficulty

the double dragon trilogy on gog are the arcade ports
and off course they know no mercy

speaking of merciless arcade games
most of snk's mid 90's beat em ups
art of fighting
art of fighting 2
fatal fury
the king of fighters series
are punishingly hard and the diffuclty may have mellowed out a bit the bosses sure as hell havent there is a reason why they are labeled snk boss syndrome
http://tvtropes.org/pmwiki/pmwiki.php/Main/SNKBoss
http://tvtropes.org/pmwiki/pmwiki.php/SNKBoss/SNKPlaymore

the nes star wars games are also brutally hard
the snes super star wars games equally so

There is a few I'm stuck on

Ninja Gaiden 2 last boss
Snatcher last gunfight
Super Mario Bros 1 and 3 are pretty tough
Sonic the Hedgehog 2 is harder than the first one
Shiren The Wanderer Mystery Dungeon 2 roguelike

Devil May Cry 3 was only slightly easier than Ninja Gaiden. The first boss grim reaper will probably kill you. And then kill you. And then ask if you would like to play on easy.

About all the old NES or arcade games people mention, I presume their main difficulty comes from the fact that you can't save the game, but if you lose all your lives, you have to restart the whole game from the very beginning?

Luckily console emulators have save states (save anywhere) so you don't have to care about such annoyances... :)

FTL and Nuclear Throne are damn impossible :(

not even to do with saving functions ( though the famicom mario 3 had a save function nintendo ripped out for the western release )
the games are also unusually unfair with difficult spikes
they require pixel perfect jumping or are just obtuse
a lot of them also send you back all the way to the start of the level and have zero check points
you die you try again from the start

and a lot of them also throw a barrage of enemies and projectiles at the player
the invincibility time is non existent
and worst of all your character jumps backwards when hit

Where did you hear about that? A Google search shows no evidence of any save feature in the Japanese version.

There is one siginificant difference between the US and Japanese versions; if you get hit in the Japanese version, you become small even if you were fully powered up and wearing Kuribo's shoe. (In the US version, getting hit while fully powered up will leave you as super mario; that's not the case in the JP version.)


Sometimes, this can be used to your advantage. For instance, in the original Castlevania, it is possible to skip the water section of 1-2 by timing a jump so that you get hit by a bat and get knocked forward onto the wall. (This is called a damage boost.)