OMG. MGS2 was amazing...back in 2001 when I bought it for $50 at launch. Also, you should be playing the PSOne version of MGSolid first, the whole story arc is being ruined.
Twin Snakes is not canon, but better than nothng, I guess...enjoy. It seems like sabotage to play them out of order, but I never thought this series was exactly for you. There is sooooo much going on, inbetween the lines, I just can't imagine how you'll understand it all.