It would be great to see you play around with time and background action. Usually you take a lot of time to savor a kill, and in general that's a great thing to do. But sometimes it helps tantalize the imagination of the audience if you're sparse with details, or even just reference a kill in passing. Also, consider playing around with flashbacks, or skipping past parts of the action. For example, one chapter on the cruise could start like this:
"The door snapped shut with a soft click. Scott yawned and wavered on his feet, he almost couldn't believe how tired he was. He certainly couldn't believe how busy the day had been. For a moment he was glad Adam wasn't back yet, and took the opportunity to collapse on the bed.
First there was that incredibly cute waiter who had served him and Adam breakfast - how many times had he 'casually' mentioned that it was almost the end of his shift? Scott smiled, remembering how the blissful moan as Scott's cock sunk into his tight ass had been muffled by Adam's own rigid shaft. Then there was that slender young Mexican he had met sunbathing by the pool while Adam was exploring the ship, who had taken a week off from UCB to celebrate his 19th birthday. His laughably impractical speedo had failed to contain his erection even before they had gotten to the supply closet. Then there was that pair of bodybuilders from New York Scott had met at the gym - boyfriends, of course - one black, one white. Scott would never forget how bold they had been in the gym shower afterwards, nor how many grins and erections they had prompted from the other men busily pretending not to watch. Scott clenched involuntarily at the memory; the black guy's penis had been huge and thrust like a jackhammer. He knew there had been a few others that day, but he'd been with so many since the start of the cruise that his memories had begun blurring together a bit. He'd remember to check the pictures he had taken on his phone tomorrow, both to remind himself of how sexy they had been and how they died.
Oh yes, they were all dead. The waiter, he remembered, Adam had strangled while he had been sitting back on Scott's dick. He remembered how he had held the waiter's wrists behind his back while Adam's strong hands tightened around his throat, his panicked eyes meeting Scott's in the mirror while Adam's cum dried on his lips. His surprisingly erotic death spasms had been what finally brought Scott to flood his beautiful ass. The Mexican kid, it turned out, had been unable to inhale through his speedo. But perhaps that had been for the best - though his arms and legs had pounded the deck while Scott held him down, his huge tool had not only gotten hard again but had also painted Scott's back with weeks of pent-up seed. Scott had hefted the boy's massive endowment for minutes afterwards while he caught his breath, amazed someone so gifted had claimed to be a virgin. Noticing his own restored erection, Scott lifted the boy's thighs and tilted his hips forward; he couldn't resist taking that too. The body builders were more difficult to recall... but Scott vividly remembered the picture he had taken afterwards of the white one spread-eagled on the bed, the letter opener embedded in his heart still standing proudly to attention from the muscled hulk's left pec.
Scott smiled. As tired as he was, the memories were too good to resist. He opened his phone and started flipping through pictures. Oh yes, there was the black one sprawled out on the bathroom floor, eyes vacantly staring at the shower head as the spray washed the jagged slice in his throat clean. And how could he forget Jeremy, the Norwegian stock broker he had met in the bathhouse at the ship's lowest level? Jeremy had been the highlight of the day. In fact, Scott remembered how..."
And so on, where Jeremy becomes the focus of that chapter.
As far as setting goes, you can't get more diverse than a cruise ship. Gyms, observation decks, bars, a mall, water parks, pools, hot tubs, a sun deck, saunas, theaters, aquatic sports, engine rooms, supply closets, life boats, and endless private berths. A gay cruise adds the possibility you'll see a bath house, and a thick layer of sexuality to all of the normal activities and settings. Orgies and creative sexual arrangements could be common, as well as intrigue. Disposing of bodies would be a simple matter of either leaving them in their berths (suspension of disbelief prevents them from smelling), or slipping the bodies over the side at night. I've got more ideas, but it's taken me almost two hours to write even this much...
