MGS is an example of how games should be made
Good: Story line is an instant classic. A wonderful game. You can select wheter to kill enemies or knock them and run away. This game has mini map. You can look from 1st persons view, despite the fact that this is a 3rd persons action game. AI is not stupid and this makes it just better. Boss fights are unique. If you get stuck you can call via codec and ask for advises, save or just talk to find out something new about characters. Design of characters are nice and characters are very memorable.
Bad: number of weapons could have been higher, but the number is statisfying. For example pistol, famas, psg-1 sniper, stinger rocket launcher and some more. You can't customise the main character (Solid Snake). Some times it looks very hard to do something, I am talking about the difficulty of the game. But what do you want, this game was made in 1999.
I started to play MGS games and I thought it would be right to start it from the first one, even though it is old. Don't even dare to play other MGS games before playing this one first.