What’s the real difference between a PG-13-rated horror flick and an R-rated horror flick? Look no further than the two new releases “Pulse” and “The Descent.”

Typically, the PG-13 one starts out as a “soft R,” which is to say, mildly gory, maybe a little sex (but no nudity) and moderate foul language

R-rated horror, on the other hand, features hardcore violence, often-graphic sex/nudity and plenty of foul language. If anything was cut out of these bad boys, it was to avoid an X, which means any subsequent DVD “unrated/director’s cut” versions, while still typically only a matter of minutes or seconds, are nonetheless the real deal for horror fans.

First exhibit: “Pulse.” Guess which rating this one is? Yep, it’s PG-13. It stars Kristen Bell (“Veronica Mars”), Ian Somerhalder (“Lost”), Samm Levine (“Freaks and Geeks”) and R&B singer Christina Milian (“Get Real”). It’s also the umpteenth Asian horror remake, this one more recent. In fact, it actually incorporates footage from the original Asian film.

As enjoyable as some of the Asian remakes have been, it’s clear that even the originals are starting to scrape the bottom of the barrel, if this movie is any indication. Also worth mentioning is that Bell, as charming as she is, is basically aping Grudge-era Sarah Michelle Gellar, as she does on “Veronica,” which is like “Buffy” minus the supernatural element. It defuses Bell of much of what most find most charming about her - just as it did, to a slightly lesser extent with Gellar on “Grudge.”

Okay, so now for the good news. Bell, however defused, is still gorgeous and talented and Milian ain’t so bad herself. There are some nice creepy moments and a surprisingly downbeat - though not entirely unexpected - ending.

Go if you like the cast, though don’t expect any witty dialogue from Bell, she’s in strictly serious mode here.

“The Descent” is a whole other animal entirely. Right off the bat, the movie sets up the emotional center of the main characters and grounds it all in wrenching reality.

After a tragic event, the three girls reunite one year later to tackle another extreme sport (the first was river rafting). It’s practically a feminist re-envisioning of the monster movie, only with the guys being C.H.U.D.s (that would be cannibalistic humanoid underground dwellers, for you non-old school horror fans) and the girls filling in the traditional male role. We’re talking eye gouging, throat chopping, neck breaking, skull crushing, gory goodness. Despite the underdeveloped characters, this film is one of those rare birds that reconfigures an old plotline for a different generation, not unlike “Scream.”

Director Neil Marshall tackled a similar approach, only with a group of six men in the underrated “Dog Soldiers.”

“The Descent” fascinates simply because it’s so rare to see an all-female dynamic that’s intelligently handled in a monster movie.

Typically, if the cast were all women in a film like this, they’d be naked in the first five minutes with feature characterizations as thin as cardboard. Here, they get fleshed out, so to speak, way more than usual for a low-budget indie horror flick, which makes this a win-win all around.

The women will have plenty to relate to, and the guys get their gore on.

Now this is how you do an intelligent horror flick that delivers smarts and fun. So, go out and support the gals this week. Veronica’s not going anywhere - she’ll be back in the fall - but this group of gals will take you places you’ve never been and might wish you hadn’t. In a good way, of course. Viva la woman!