Half-Life is a must have for the PS2.
You start off playing as a man who is Gordon Freeman, who is a scientist and is working in a underground research facility. When the game first starts off it's just another day while you late for work and trying to get there. Then you finally get there you and others start an experiment are something then everything goes horribly wrong. Half Life has a fantastic story to it that's one of the main reasons I played the game.
The graphics don't look nearly as good today as they did back then but there still ok, you have a nice selection of weapons that you can use. The sound is good to all the monsters are enemies look nice and are kind of creepy.
Overall Half Life is defiantly a game you must play is you like FPS its just great a lot of fun with an amazing story, It doesn't cost very much so that makes it even better.