The players consist of: Basheba, a human cleric of Bahamut who is cursed with a from of pseudo-vampirism (laurie_robey), Kalan, a djinnblood sorcerer/rogue with a penchant for sneakery and flashy acrobatics (jamesbarrett), and Doryyn (sirfox), a dual-wielding jackalwere seaman. They have been joined by an NPC, Vellardus, who was the first mate on the ship they were traveling on.
The scenario is a good ol' S&S classic — a mysterious island has been shoved up from the sea floor, causing all sorts of horrible weirdness, and the heroes have come ashore on it. In this particular case, the heroes swam ashore, because their ship was driven onto a barrier reef by its siren-maddened captain, helped along by sea devils, who eventually climbed aboard and began tearing apart the crew. To the players' credit, they almost managed to save the ship, even though I designed the adventure so that this was practically impossible to do.
Once the sirens (harpies) and sahuagin were both involved, it rapidly became a massacre. Other than Vellardus, even the few NPCs who had the presence of mind to flee the sinking ship tended to find themselves fleeing into the waiting arms of the hungry sea devils. The PCs and Vellardus, once it became clear that "escape" was the victory condition for this encounter, abandoned ship and headed for the island shore. Unfortunately, the rest of the crew were devoured. (In an ironic twist, however, one of the harpies who had been harassing the PCs was also devoured, when the sea devils realized it was bloodied and descended upon it like piranha.
The survivors, all four of them, rested panting on the beach for a while, then got their bearings. They decided to head for the hull of another wrecked ship, rather confusingly high on the shoreline, but before they got off the beach they were attacked by the giant enemy crab that everybody knew had to be coming, and four of its young. This fight was a bit of a slog, because the crabs resisted most of the damage thrown their way until they were bloodied, at which point the shell was cracked and they were as vulnerable as any other creature. When we ended the session, the PCs had used some of their daily powers and several of their healing surges, but were in overall decent shape still.
From a GMing perspective, it was ... interesting. Game prep was easy; easy-peasy pushbutton adventure creation. Even a huge mess of an encounter like the shipwreck didn't actually require that much fiddly mechanical work. Most of the sahuagin and ship's crew were more like scenery than anything else — the bulk of the encounter was skill checks or PCs vs. harpies. I had stat blocks for the sea devils and for the ship's crew if they were necessary, but I only referenced them once or twice and could have easily faked it.
On the other hand, combat was a big ol' slog. Everything (that isn't a minion, anyway) has SO MANY HIT POINTS. 0.o According to the presented math of encounter creation, these encounters were right on for the group, but the monsters' defenses seemed to be awfully high (or the PCs' attacks awfully low), so a lot of turns were spent missing the target, and even when the target was hit most of the attacks didn't do a whole lot of damage relative to the creature's overall state.
So, net result ... not sure how I like it so far. Maybe I should just halve all the monsters' hit points?