I agree with all of what scott said, but I sort of agree with none of it at the same time. HL2 *was* fun, and there's no denying that it's a great game. My problem had nothing to do with the gimmicks. I mean, the only reason I ever referred to them as gimmicks at all was because of the way they were placed in the game, not because of what they *were*. The variety in gameplay was very much appreciated and was really refreshing... at least, initially. As you'd get to a new area you'd always have something fresh, and that was great! The problem was that you'd then spend the next few hours doing nothing but that "fresh" thing they introduced, and it would veeery, very quickly become stale, redundant, and boring as fuck. If you took what HL2 is gameplay-wise and tossed it into a big bowl and mixed it up, it would be awesome. Don't introduce mechanics, overuse them, then abandon them. IMO, that's bad design and nothing more.
The world is fun, I enjoy the art design (it's sort of slightly generic yet really unique in its little touches at the same time, and it works great in the end), and the production values are sky high. That's all great stuff. But there's the aforementioned no-story-whatsoever-problem, and it had the most boring and fucking plastic characters of any game ever (rendering all the amazing voicework and facial animation completely ineffectual). Seriously, most characters in games interest me even if not terribly well done, but for the first time possibly ever I found myself literally just wanting to shoot them in the face... not because I hated them, but because I was so utterly indifferent to their stupid, whiny, poorly-presented situation that I just wanted to kill them so they'd shut up and I could get on with it. And all the fucking Gordan-worshiping was the cheesiest and lamest crap I've ever heard, even in context of the original game's story. Just stupid. So you take those two and combine them with the aforementioned gameplay-chunks that had you doing the same shit over and over until they threw something new at you... and you have my complaints, plain and simple.
That doesn't mean the game isn't great, and I fully acknowledge all that HL2 did right (can't speak for the episodes because I've no interest in them and haven't tried them), and I even acknowledged that HL2 was a better *game* than Doom 3. The difference? For me, Doom 3 was a better experience. I was just running around shooting stuff, but that was the point, and there was decent enemy variety, great atmosphere, and fun level design. So while I know full well it wasn't nearly as good a game as HL2, the specific problems with HL2 really hit my sore spots, where Doom 3 didn't. Doom 3's story was really pretty lame all things considered, but it was still world's better than HL2 simply because HL2 *didn't have one*... and even Doom 3's lame characters were more convincing than those of HL2 simply because they fit the world and were consistent. It *felt* like a cheesy horror movie with tons of gore and atmosphere and characters who were waiting around to die, and that's basically what it was. HL2 *felt* like a sprawling epic of gameplay, story, and design... but the fact that it sort of botched the first one via bad pacing and forgot to include the second one somehow, I just couldn't bring myself to truly like it. I tried to play through it a 2nd time and gave up about four hours in. Despite popular opinion, I *want* to like HL2 (irregardless of my feelings for Steam, etc.). I just... can't.
Anyway, sorry to go off on a tangent there. I really just wanted to address what I meant all the times I called HL2 gimmicky.
And I don't think Portal qualifies as gimmicky, either. It's built around a concept... that's only a "gimmick" if it's shallow or poorly executed. If it works, it's a design principle.
