I only played a little bit as well and I think it's the first and second level or something but.... well.... It didn't capture me, I'll have to try again because everybody seems to love that game and I want to love it too!
The tanker mission in MGS2 was short and disappointing but thats because it evolved around the character raiden. The Big Shell. Enjoyed it a lot. Had so many instances where the game wanted you to go back and forth to different buildings to do certain missions.
MGS3 - Love the camo system! Felt good using the CQC system on enemies and carry supplies and food when you're running low on stamina.