When they were pink and green. Ah memories...

Ah yes. They were shades of red, green and sometimes yellow. Those were the days... Just kidding of course (or maybe not...).

Anyway, never heard of it. I'm seeing here it came out on every single home computer of the time apparently, but it doesn't look "open world"...

#44 - Tenchu: Stealth Assassins

Like I said in my hint, this game gave me the feeling of being a ninja more than any other. You'd run on rooftops looking for the best way to strike at your enemies, you had an arsenal of cool weapons from the classic shuriken and smoke bombs to the more wacky like the poisoned rice and the decoy whistle (which imitates animals to throw off guards). 

The game would reward you for playing stealthily but you could always take on a guard or two by yourself should you get caught. Missions are increasingly challenging and there's three differents enemy layouts for increased replayability. Much recommended for anyone who ever dreamed of being a kickass ninja.

#43 Hint: NES game with an open world, power ups that allow you to progress further, no hand holding whatsoever and insane difficulty.

The original Zelda?

@: mZuzek & Teeqoz: Both wrong.

#44
The Elder Scrolls: Morrowind (PC/Xbox, 2002)
guessed by mZuzek

For many video game fans of my generation, Final Fantasy VII was the role-playing game that invaded their imaginations and turned them into lifelong RPG fans. For me, that game was Morrowind. What Morrowind impressed upon me, apart from its excellent graphics, sound design, and combat system, was its sense of freedom. From the very beginning of the game, I had the freedom to choose the name, appearance, and attributes of my character. Once in Vvardenfell, I could stay and go as I pleased, taking on quests, interacting with characters and events that shared only a marginal connection to the main story arc, or simply exploring Morrowind's expansive and richly detailed game world.

Castlevania II?

I guess there's a lot of NES games that fit my description... not Castlevania. The game I'm looking for has no save option and a limited number of continues which is part of the reason it's so hard to beat.

Both Warcraft and Starcraft are great in my opinion, so you are all forgiven ;)

Anyway, number 44 was Ogre Battle 64.

Number 43 is a solid member of one of the most famous game franchise which starts like a goat simulator.