Try this: download an MSX emulator and get hold of Metal Gear - the first and original.
Play it. It's not perfect - there's a limit with what you can do with 128k - but it's good fun. The MSX 2's colour palette is used very well, there are massive seemingly invincible bosses to defeat, and you will have to draw a map using pen and paper to avoid getting lost.

Once you've finished Metal Gear (and it took me three or four weeks back in the day if I remember correctly) get hold of Solid Snake: Metal Gear 2 for the MSX 2.

The music is suberb, the AI is better, the sprites are more funky, and the game is four times as big. According to legend, the first batch of cartridges sold out in a day in Japan. I still have mine in the original box.

And if you get past the marsh behind Building 1, let me know - I never did figure that out.