MGS 1 was my first mature rated game, and I actually managed to stumble my 8 or 9 year old way through a decent portion of the game with no idea what I was doing before my mother threw it away (claiming I must have done something with it, which I never got punished for so I don't think my dad believed)

When I was a teenager, the second one came out and I was hooked after playing the tanker level, even though I didn't get to play as Snake.

Honestly I think 1&2 are the ones you really need to get used to. 3 has some wonky sections as the camera changes angles, but for the most part it's pretty close to "modern action/rpg"

I feel like the only time I ever hear people talking about this series is in the context of memes like Revolver Ocelot (Revolver Ocelot). The games really don't get enough love.