It's to encourage the exploration aspects of the game. You have to physically check doors to see which ones open and which ones don't. Just note in Black Mesa that some doors are one-way or are barricaded. You might have to find a route around those one-way doors and some barricaded ones may need to have their barriers removed before you can go through.

Once you get to know the maps more, you won't need to check most doors again outside those needed for progress and for looking for supplies to keep Gordon alive and armed.

Originally posted by Engamer01:

It's to encourage the exploration aspects of the game. You have to physically check doors to see which ones open and which ones don't. Just note in Black Mesa that some doors are one-way or are barricaded. You might have to find a route around those one-way doors and some barricaded ones may need to have their barriers removed before you can go through.

Once you get to know the maps more, you won't need to check most doors again outside those needed for progress and for looking for supplies to keep Gordon alive and armed.

No it doesn't work like that, if you want to encourage exploration than make it seems less than a corridor by adding extra room and optional paths, the strength of the game is definitely when you are walking trough the game without realising the map structure.

You shouldn't need prior map knowledge to play a single player linear game cause that would just only hint about the bad navigation of the game.