Quick roundup of things I noticed that might be important killer clues, and my interpretation of them.
Jorick - "blah blah blah I'll kill you." Oftentimes used as a major red herring to point fingers in the wrong direction, but that doesn't discount me from being the killer. It also shouldn't make me the prime suspect, but I'm obviously biased. Nat then dying in this post was purely incidental and based on his own role, nothing to do with me.
Seravee - Face showed nothing, no emotion, after watching Shy get shot in the face. Could be shock, could be iron-willed control over her emotions/expression, could be a lack of empathy, could be she knew it was going to happen and was able to prepare herself. Inconclusive at this point. The emotion shown in the next segment, with Squee talking to her, could have been skilled acting, so that doesn't exonerate her. Oh, also, her not going to the challenge makes me think she just didn't send an answer in, which is an educated guess based on knowing that she's a busy lady, but I can't be sure about this. The fact that she apparently had some alone time with the Master and his assistant is worth considering though, the whole thing could have been an in-story ploy to get a chance to talk to him privately.
Jordan - "...watched as all the other victims slowly filed into the lounge." Seems to indicate a mindset of himself being one of the victims, which would mean he's not the killer, but it could of course just be some narrative flair from the author rather than his actual thoughts. Shared a look with Svenn, could mean anything or nothing.
Vordak - Anxious, though trying to hide it. Is he anxious because of the situation at hand, or because he was psyching himself up for his first kill? Inconclusive but noteworthy. The fact that he's being hands off with the puzzle is interesting though. Perhaps the killer doesn't want to taint the integrity of the game and is letting the others actually solve it?
Svenn - Dislikes Drakel, apparently. Also seems to have an issue with me and Nat. On friendly terms with Knightshade in some fashion. Shared a look with Jordan, could mean anything or nothing. Gets rather pissy about Squee knocking him down a couple pegs. All of the people he got upset with were part of a couple (though Squee also made him look dumb), could be his character's jealousy of their relationships. I'm of the feeling that his being annoyed by others isn't enough to point to him being the killer, could just be an ornery little shit.
Drakel - Dislikes Svenn, apparently. The lack of expression on his face when Squee died could again be anything from shock to lack of empathy, nothing solid to conclude from it without further evidence.
mbl - Chatting with the Master? Very suspicious. Too suspicious, even. I feel like this is a major red herring, but your interpretation may vary. Pretty sure that was just some thing to explain away why he wasn't in the challenge, since he didn't send an answer in and thus shouldn't have logically been there participating in the story.
Alphakoka - Helped to solve the puzzle for his team. My guess is that this is meaningless, just a way to show that he sent in the right answer.
Knightshade - Helped to solve the puzzle for his team, same conclusion as above.
The whole thing of splitting off into two groups may be important. Knightshade, Squee, Drakel, Svenn, and Jordan went with the Master; Alpha, K-97, Nat, Jorick, and Vordak; Seravee and mbl were not present for the challenge. Ignore the poor dead bastards as killer suspects, obviously. I'm thinking that the Master might have wanted to put some distance between himself and the killer, but you never know, could have just been random draw stuff going on that means nothing.
Another grouping might be even more important though: those who were called forward. Alpha, K-97, Knightshade and Squee were called forward, and only Alpha and Knightshade made it through alive. It stands to reason that one of them might have been the person to kill Squee, as they were nearby when the lights went out. It doesn't say how long they were in the dark, and it said people started to run around. As I said, it stands to reason that one of them may be the culprit... which is exactly why I'm discounting them from my voting choice at the present time. They're too bloody obvious. I'm guessing that those four were all the people who sent in the hexagon arrangement idea (the thing about breaking planks to make smaller rectangular cages was my actual idea, not just a thing Shy made up, heh), so their proximity was incidental rather than planned out. Given the supreme lack of evidence pointing at either of them and this seeming like a massive red herring to me, I don't think either of them are the killer at the present moment.
Oh, and as it turns out, it seems that there actually isn't a traditional matchmaker role in this game. One of each pair died (literally all the pairs, not just the romantic ones), but the other remains alive. This leads me to believe that all the pairings were shenanigans that Shy threw together just to screw with us and allow some easier story bits (like how in this post the first two segments were focused on the couples). I know my own role has nothing to do with Nat's deranged cop thing, and I'd be surprised if there's any linked nonsense with the other two either. This just goes along with my previous assessment that the pairs are mostly meaningless, with the simple change that all three were nonsense instead of just two.
So after putting that all together and reading the post a couple more times, my top killer suspect at the moment is Vordak. Svenn's dislike of people was sorta fishy, Seravee and Drakel's lack of apparent emotion were cause for suspicion, and Alpha and Knightshade having very little in the way of character development and activity in the post send off some minor alarms in my mind, but Vordak is the one that I keep coming back to. The anxiety and the imperious manner he had during the challenge make me think that he's either the killer or perhaps working will the killer/Master and feels like he's better than everyone else. Putting that manner off all to him being rich would stretch credibility, seeing as Seravee is also supposed to be rich but acts on a level manner with Squee. So I think I'll be voting for Vordak, unless someone else comes along and gives a more compelling interpretation of the evidence at hand.