Sorry inforno, these comments aren't directed at you, but at the thread as a whole as I think we need some new terms and definitions.
Linear means you can draw on a line exactly what will happen to the player. You play on-a-rail with no option to choose a course. (Example: Doom)
Branching-linear means you aren't limited to one set course, but are still limited in what you can do to a few simple options. This can also lead to one or many conclusions (linear or branching ends). (Example: Neverwinter Nights)
Non-linear means you can do what you want when you want for whatever outcome you want. (Example: The Sims)
Now that that's defined, Myst is branching-linear with branching ends. (Puzzles have no predefined order, not all puzzles need to be solved in order to complete the game, and there are four (?) possible endings.) Half-Life 1 & 2 are linear. (Puzzles and plot points are sequential and there is one successful outcome, despite the silly either/or choice at the end of each.)
Is linearity a bad thing? Absolutely not, if it fits the game nicely and offers memorable moments, which HL2 is full of. It's a design decision that generally is decided by the genre. Most FPSs are linear. Branching-linearity is mostly seen in RPGs. There are exceptions of course, but most of those come from genre-hybrids. Deus Ex is a prime example.
As a simple rule, if someone has a problem with linearity, they should be playing something else.
And now, a rant.
I've been seeing gamers give reviews the same as magazines and websites. Back in the day, gamers would actually finish a game before passing judgment. Now they play for a few hours and judge on comparisons. "It's like such-and-such, but lacks the this-and-that of whats-it-called."
They also don't seem to spend enough time in singleplayer. I can't remember how many people I've talked to who said Counter Strike is the best game ever and said they never played Half-Life, even though at the time they had to have it to play the mod! I play SP almost exclusively and found Half-Life 2 to be very rewarding in that aspect.
I also enjoyed Myst, Riven, and
Rama, having completed each. Does anyone else remember PC Gamer saying Riven couldn't be completed without a strategy guide? I beat it in three days without one, with only one page of notes. It was a cake walk after cutting my teeth on Myst and Rama, which took months each.
Okay, I'm done. Again, these comments aren't directed at anyone in particular, so I'm sorry if they offend.