No, it was not.
[omgspoilers]You need to shoot the shit out of monolith guys around, till portal opens. Step in and repeat the process ... around 20 times.
Strange. I think it's a bug, since my friend also had it - you don't get the Guide quest after you loot Ghost.
Hmm, I somewhat disagree, though it's debatable and depends on what kind of game you're making. Yes, conventional game development practice says that you need to put challenges before the player, but in a nature to make them fun to overcome - not too easy, and not too hard. Everything should flow fluidly in a way so as the player would have an illusion of accomplishment, eventhough we held his hand most of the time. This belief stems from the axiom that fun is the quintessence of computer game. Everything is subject to fun; if playing your game is not fun, then the product is deemed a failure.
But is this necessarily correct? Warren Spector had an opinion article half a year back in Escapist Magazine (can't be arsed to find it ) where he stated that games will be viewed as purely entertainment tool, inferior to art and lacking recognition, until we start to make games which have more to their internal value than pure fun. Games which carry political and social connotation, games that are played not with mere enjoyment in mind. Games which will even irritate players to hell to achieve their goal of presenting a particular idea.
Anyway, we seem to differ even in the very basic notions of what a correct decision-making structure in the game should look like. To some, any backtracking is a nuisance and they want to steam ahead to the end. To others, carefully examining all the nooks and contemplating hidden meanings is the proper way. Because of this it's impossible to devise universal postulates of the game flow. This is why we have very different games on the market. I look forward to seeing even more radical approaches in the future, though the reliance on big publisher's capital is a huge problem here.