I don't remember the game well but I recall finding the part on the fan boat to be a grind. The first time I tried to play through the game I stopped halfway through that part. The second time I forced my way through it. There are a couple of other isntances that I can't recall the specifics of.
Toasty above mentions the dead ambience and I have to completely agree. Although, I do conceed that the world should feel a bit dead considering it has been taken over by an interdimensional race. Also, Gordon is not that interesting of a protagonist.