Proxy is supposedly smart right? The ending you offer up makes him absolutely as dumb as a doornail (unless I misunderstood). I was expecting something more and thus thought "Surely it's not that easy" and I picked wrong the first two times as I wasn't paying attention to the particular visual hint that made it obvious.
The dialogue would fit and make sense if he was deliberately taunting you and that was what I was going on. I suspected proxy was jumping between bodies after every kill and playing mind games by creating dissent and throwing suspiscions left and right. And there was also a visual cue of some kind of jumping going on after every kill which also lead me to believe I had to pay attention to anyone saying stuff out of character. I think if this were the case it would have been much more enjoyable as in one instance Jordy acts like he is not aware of stuff he said earlier and the young girl repeats a sentence like she's not uttered it before. Also Aleph repeats something that girl said so it seemed like Proxy was jumping between people and that made it a lot more interesting.
To sum it up:
My initial take on the game was that Proxy was jumping around to different people while conducting the killing (which is what threw me off), but it seems he is inside the same person all along - this is what makes it cheesy bad for me - while I really enjoyed the buildup that suggested he could be in anyone in any given instant.
Like another poster before me noted, the "playable" character should also be a choice logically.
Also it seems the dialogue wasn't proof read ;) which is forgivable, but it does detract from the overall enjoyment.
I think you could have a way better murder mystery with a few tweaks as the premise is interesting enough.
About the freezing problem: I noticed it only occured if I fast forwarded all the way til the choice was available to me. If I stopped the fast forward before that point it was fine.