Hmm, to be honest I'm surprised this one made it onto "Movie Defense Force" largely because I wasn't aware that it really needed defending. It's "failure" seemed to be the result of the movie not succeeding immediately in theaters, it however succeeded well enough overall that it received a sequel a few years later. Not only that but it's popular enough within the nerd culture that when "Critical Miss" did a joke about the Lamnent Configuration from "Hellraiser" a number of people thought it was a joke about "Silent Hill", which should say something about the current generation. The movies also did well enough where Universal Studios made "Silent Hill" the theme of their Halloween event (last year I believe).
That said, unlike my usual comments about how things need to be judged based on the relative handling of the material, I will say that "Silent Hill" actually fared pretty well given what a train wreck it was in that respect. They seemed to have little problem shying away from the gore, but at the same time they seemed to get away from the whole idea of what the cult operating in the town was all about, whether that was for fear of offending people, or the writers wanting to get some jibes in at Christians, I have no idea. It also features perhaps the absolute dumbest scene in any movie to date which involves (Spoiler to the right, since I can't make spoiler space work today for some reason) a certain lady cop telling the homicidal cultists she is out of bullets after successfully holding them at bay with an empty gun, which she could have continued to do.
The Silent Hill Sequel (more spoilers for anyone who cares) on a lot of levels managed to be a little more loyal to the source material, which makes it kind of funny when I run into fan boys who slam it harder than the first one for whatever reason. Silent Hill 2 was pretty much using the plot from the third game, albeit instead of the twist that all the monsters the protaganists seeing are actually people and she's hallucinating (albeit with the source of this coming from Silent Hill) it's handled in a more straightforward "they are real" sense. They did it more or less right, except for the actually fairly clever twist in a storyline that was inferior to the first two games in the series, which is more or less what sold the entire thing as far as it went. The idea that the monsters are people is an ancient one, but it was interesting when you learned that slightly easier combat in some areas compared to the harder survivial aspect of the first two was simply to bait you given that the ending was largely determined by how many people you killed thinking they were monsters.
It's also worth noting that the first Silent Hill movie was NOT even attempting to follow a game storyline, instead it was blending plot points from Silent Hill 1 and 2 together into one narrative. The actual twist ending as far as it went is actually the twist from the first game, not the second.
To be honest though, given that the guys holding the license have been unable to string together anything more than a mediocre "Silent Hill" game since the third one, I think the movie guys deserve some slack when dealing with material no professional has been able to write well in a long time. I suspect largely because of fears over backlash that started when the Silent Hill team got complaints about how the demo for "Silent Hill 2" went too far causing them to edit "Silent Hill 2" for content (true story) with later games being done as if they were tip toeing across a mine field, wanting to make the game messed up, but not TOO messed up, as a result it failed to deliver to genere fans who expected the ante to be upped in each sequel.
It's also noteworthy that people tend to project onto "Silent Hill" quite a bit, and to be honest a lot of the explanations people use for how things work and fit together, and how everything is based on the psyche of the latest victim, are based on theories that were presented in the game that people ran with beyond what was actually said, especially when it came to "Silent Hill 2". Totally overlooking that the conclusions could have been entirely wrong, especially in light of the facts established in SH1 where the driving force was actually confronted directly. I've often felt that Silent Hill kind of suffered from writers figuring that they liked the Fan's explanations a bit better than what they originally thought of, and then ran with them. Those explanations while fairly elegant do make for some pretty craptastic and predictable storytelling. It also tends to overlook why a driving intelligence wouldn't want to keep something as powerful and intimidating as Pyramid head around as a minion even after the guy that inspired the intelligence had moved on. One of the few things I've always boggled at is why certain fans object to his appearance, while at the same time argueing there is a malevolent intelligence at work. Nobody complains about the nurses, which are arguably a sign that the town does like to keep a few stock tricks in it's bag.