Six hours total to beat the game? That's a complete low-ball estimate. The only way I can see that is if you've already played the PSX game and remeber the level design and how to beat the bosses. I had never played an MGS game before Twin Snakes and I'd say it probably took me twelve to fifteen hours to complete.
That might explain a few things then. I was a huge Metal Gear fan ("Uh oh! The truck have started to move!"
), at least until MGS 2. The PSX version of 1 (and the Gamecube remake) will always hold a treasured place in my gaming heart.
And from my review
"Unfortunately, there are some issues. First off, the game is short. Very short. The average gamer will finish this game in six hours or so. Half of that are the outstanding cinema scenes. On successive run-throughs, if you skip everything important, the game can easily be finished in about two hours. For that matter, the second CD is almost nothing but either boss fights or cinemas."
I do remember keeping an eye out on the clock as I played this title for review, as I knew that other reviews had stated this game was short.
One thing to remember - time to completion times vary wildly from person to person.