That's how it is for most games, people are super-hyped for it in it's last moments before it's released, then long after it's release, people have beaten it/played it many times, so the hype dies down, people still think Portal 2 is an amazing game, i still do, it's just that it seems odd to continue being hyped up over a game that's been out long after it's release
Team Fortress 2 still gets a lot of hype because that has many updates, some are more important than others, like the Uber Update, people awaited for the final day when the Medic items were revealed and they got the surprise of Meet the Medic at the end, though some people predicted Meet the Medic at the end because well... it's the 'Uber' Update, also, people just jump to conclusions and probably said that anything relating would mean that Meet the Medic is coming out
Poll