This was a really nice surprise!
First and foremost, I really like the art style, the setting and the ambience. It's pretty oppresive and lonely, specially during the sections in the dark.
I really liked the gameplay and the puzzles. I had no problems with the filter system; it was actually really well made and it gave a sense of urgency and dread, so great job in that regard.
The music and the sound design were also really good, really fitting for the tone and ambience.
I think what I liked the least were some of the chase scenes, but they weren't really frustrating. I managed to get the 2 endings and my playtime was about 19 minutes. I liked the one where he drinks the Reptia, but the other one wasn't really my cup of tea. I would have loved more endings!
While I didn't really find the regular reptiles threatening, the giant one (was it subject 6?) was more intimidating and creepy, it kinda reminded me of Mr. Gray from The Dreamcatcher by Stephen King.
Overall, this was a reaaally good game, with a lot of attention to detail. I found no bugs whatsoever and I can tell you put a lot of passion and effort on this!