[hypertele-Xii]

I think you are remembering things unfavorably. Half-Life has many dead ends that do not advance the game, but contain nuggets of story activated by player interaction.

Maybe you just missed them all!

Just off the top of my head from the start of the game: Activating the alarm from the button on the reception desk, getting the guard into trouble. Going into the kitchen and playing with the microwave cassarole (referenced from later sequel!). Opening lockers in the locker room (looking at people's stuff), getting the hazard suit and heading back (if you try to proceed without suit, guard will tell you to go get it - nonlinear maps!). Pressing the broken elevator button, sending people plummeting. Opening the dumpster to find the hiding scientist. Operating vending machines.

Did Wolfenstein or Doom have anything like this? In Wolfenstein you can optionally open cells and find hidden doors behind walls. In Doom you can push buttons, and you are always required to do so to proceed.