Overall I enjoyed MGS but I was expecting more given the legendary status the game holds.
I re-visited MGS (on PS1) this week and here are my thoughts.
Same as you I played it when it came out in 1998 and thought it was short, but was very impressed by the game and how novel it was at the time.
Playing it today however, I reached the part where you have to deal with the PAL key puzzle. I hated all the backtracking involved. For example having to climb three stories down to then roam around like an idiot on a ditch while taking damage. How was I supposed to know a rat ate it? Then I climb back up and formally begin the temperature puzzle. Once I realized I had to backtrack back and forth two more times way back to previous areas so I could cool or warm the PAL key, I stopped playing. Patient gamer I was not!
I totally erased these annoying parts off my memory. All I remember was how cool the game was, the ambiance and setting. Makes me realize how different (and tolerant) my expectations were when I was younger.
So yeah some of the gameplay design shows its age, but I also understand how ground breaking it was when it came out. In spite of what I mentioned, the game managed to get me hooked. I just been infected with how easy games are today.