Originally Posted by Blowie
wasn't black mesa the place where you save eli, the prison or some sort ?
Namrac's already explained it for you. but I have to say.. if you dont even know what black mesa is, or where its place is in the storyline. Then you really are missing out on the entire essence of the half life story. Part of the enjoyment of HL2 is the sheer depth to the story line. If you didnt already know, at the start of HL1 gordon freeman has just started work as an assistant at black mesa where most of the elder characters in HL2 previously worked. There was an accident with the portal machine and a portal to another world was opened. Littering black mesa and eventually the world with various different species of aliens including the combine who eventually take over entirely and use Dr.Breen, originally the boss of black mesa, as the frontman for the new empire.
You start off HL2 where you end HL1, waking from a black mass. At the end of Half-Life G-Man, impressed by your work, gives Gordon a choice between his death or working for the G-Man. Half-Life 2 assumes he chose life over death. After you choose to work for him G-Man puts you in a slow-time-warp you see. Thats where he wakes you up from at the beginning of Half life 2. G-man tries to take you back at the end of HL2 after effectively achieving your goal by killing Dr.Breen. But you and Alyx are both protected from being taken back into the time-warp by your helpful friends, the Vortigaunts :]
You really need to read into it. Read into G-Man, the combine. Everything. Its spectaculary interesting. Read here
to find out everything else in a nutshell
Sorry for the long post lol I just hate it when someone doesnt understand the HL2 story. THey're missing out on so much!