Joocifer's solution has got pretty much everything covered. What I'd like to do here is offer a slightly different approach to the tough VR missions you will have to pass as Snake in his MGS1 form.
For starters you will need to pass all of the other VR Missions as Snake (MGS2), Pliskin and Tuxedo Snake before taking on the Classic Snake VR Missions. As expected Classic Snake missions are very hard and to add on to the difficulty, the radar is switched off for ALL of Classic Snake's missions! To aid anyone struggling with these missions, I have made videos with commentary covering almost every Classic Snake mission.
I know that you can find anything you need via YouTube but what I try to do with my videos is make the missions as straight-forward, simple and easy as possible for those viewing, kind of like a Snake VR Training for dummies, or should I say rookies in this case. Of course, you will need to be skilled enough just to reach this set of missions so all shouldn't be so bad if you've made it this far.
I won't post up all the videos separately as I do have each individual set of missions in a handy playlist via YouTube (ie. Elimination Mode, Bomb Disposal Mode etc etc), instead, I'll just post up the first mission of each category.
I hope these videos do help people out and if anyone needs help with the earlier stages of Snake, I can make more videos if you'd like me to (to a certain extent). Here's the links to each of the playlist:
Sneaking - Sneaking Levels as Snake (MGS1)Sneaking - Elimination Levels as Snake (MGS1)Weapons Level(s) as Snake (MGS1) Weapon levels are purely skill-based and don't really allow for much advice besides aim & shoot. If anyone is really struggling with a particular weapon I'd be happy to try and help out.
Variety Mode as Snake (MGS1)Bomb Disposal Mode as Snake (MGS1)Elimination Mode as Snake (MGS1)Hold Up Mode as Snake (MGS1)Good luck!