Ok, so by watching ppl still argue around what continuos run is and what is not i offer you a more precise way to define it.
There is a particular way HL1\2 Engine treats the game. That is, when you press “new game” (or start singleplayer in any way) - a new so-called “unit” is created and everything goes inside that unit.
Let me explain. Say you wanna cross a transition over two maps. When you touch the changelevel trigger - it doesn’t immidietly change the map to the next one. First, it stores the previous map state in a special save file (usually called .HL1, .HL2, .HL3 (no pun intended) etc.). These special savefiles are valid throught the same unit gameplay. So if you need for whatever reason return to the previous map - the engine will restore it’s state from the corresponding .HLx savefile.
Now, the “map” command effectively starts the new unit gameplay. That means if you reach a new chapter in the game, then go to main menu and restart that chapter - you effectively have just started a new unit, all your progress is lost. The only thing that makes it appear as if you have some progress is pre-placed weapons and items the player presumably will have at this point in the game. Even if you return to the previous map - there will be no tracks of what you previously did, all the combine solders will be alive, everything will be new, nothing’s destroyed.
So, to conclude, i offer you all a definition of a continuos run - the one-unit run. Any action that makes the eninge start a new unit breaks the continuity.
I await your opinions on this.