This reworked Nintendo Entertainment System port of the MSX version of Metal Gear first came out in 1987 (1988 in North America), just three months after the original. While it’s considered (rightly) to be inferior to the original MSX version it was a major hit and went on to sell over a million units in the United States alone.
The layout of levels is partially different in this version, and the game has a few quirks that make it more of a pain in the butt to play in places (like, for example, not being able to put the gas mask on before entering a gas room if the entry door requires a key card), and easier in others (in some places enemies that were in the original are missing, and also dodging guards in certain rooms is easier). The gameplay in general is the same as before, though. Enemies detect you using a ‘line-of-sight’ system, rather than a conical view. Solid Snake can punch enemies until he has a weapon and ammunition, but even then it’s worth waiting until he has the silencer before shooting people, otherwise you’ll just alert the guards with the noise of the gun.
Graphically it’s somewhat different to the MSX original, with many of the backgrounds having been re-drawn and new locations added, and – to be honest – they look pretty rough overall (especially the trees which look like a patchwork quilt of square characters). There are also new animated sequences that have been added (like the parachute drop at the beginning of the game), but these don’t add much to the game.
The biggest stand-out is the translation, which is terrible, with laughably bad use of English. Overall, though, Metal Gear on the NES is okay to play. If I had to choose between this and playing the MSX original, I’d choose the original every time.