A long time ago I played either the first Metal gear solid on a PC running windows. Now, I really can't remember if it was the Windows port, or the PlayStation game in an emulator. Whatever the case may be, the game came on two discs. One was the story mode (for lack of a better way of putting it) and the other was a number of "VR" (for Virtual Reality) missions. I found the VR missions much more exciting, as they were small, puzzle like, stealth challenges. On the other hand I found the story mode boring, because the story kept disturbing the gameplay. My personal preference would be for longer intervals of gaming between story segments, or just no story at all.
I have not played the other three Metal gear solid titles. Were any of them released with a bonus disc of missions like the first was? If so which one? Otherwise, do any of them feature more than 10 hours of interactive game time or (alternatively) skippable story bits?