Inferno takes a different route than previous Hellraiser films, and originally, the script wasn't even meant as a Hellraiser film, which you could sort of guess by watching the final product. Instead of what we got before, this is much more a psychological-based horror than straight-out gore. It's an interesting idea, but comes out a mixed bag.
The special effects in the film are okay for straight-to-video. I'll say again that the Cenobite designs are pretty awful (Torso, while it's nice to be reminded of Chatterer, just doesn't do it for me), but because the movie isn't as focused on the Cenobites as the main character's battle with his sanity, it doesn't hurt the film as much as it did the third or fourth movies. Gore throughout is moderately decent - the hook-whip scene in particular was pretty solid, and the sound effects nailed it (along with a few other scenes). While there's not that many explicitly gory scenes, plenty of aftermath is seen, and all-in-all, it worked out.
The cast wasn't amazing here. You could certainly get the straight-to-video feeling from them. Craig Sheffer was about 50/50, and his narration didn't particularly help. He certainly got hokey at times, especially toward the end. Nicholas Turturro didn't shine here either, and came across as generally weak. Of course, Doug Bradley did just fine as Pinhead, though didn't have as quotable lines as he's had in the past. I did like briefly seeing Kathryn Joosten (of The West Wing fame), and overall, I enjoyed James Remar's performance, though his character didn't make a bunch of sense.
Which is the biggest issue with the movie, being the story, which just feels both underdeveloped and, at times, nonsensical. The time-frame stated in the film is entirely unrealistic, and though toward the end we're given some answers, I can't help but still feel unsatisfied. It doesn't help that some portions of the movie just look rather amateurish (I'm happy to say, though, that the director, Scott Derrickson, greatly improved, and went on to direct 2012's Sinister, an enjoyable film), and some sequences (the cowboy bar, for instance) just seem both random and not relevant to the plot.
I've seen this film some three or four times prior, and I probably liked it more in the past than what I do now. That said, I do think I'd prefer this one over the third or fourth Hellraisers, despite their generally more, for lack of a better term, 'Hellraiser' feel. Inferno has some interesting ideas, and I think a more clear-cut script would have helped the movie out greatly. Nowhere near the best the series has to offer, but more enjoyable, despite its flaws, than the third and fourth movies, Hellraiser: Inferno would probably disappoint many going into it, but I've found it consistently an okay film. 6.5/10 (rounded down to 6/10 to fit site's format).