I found Betrayer to be both unsettling and fun to play. Everything you encounter is shrouded in mystery, be it your marooned situation, the person that shoots an arrow in your path to pass along a message, or the "darkness" you enter upon ringing the settlements' bells. At first I found it to be a rather unforgiving game. There's not a whole lot of handholding that happens with this: Here is your bow. Be careful with your ammo. Try not to die to ravening conquistadors on your way in. Pick up some clues and try to piece together what the hell happened if you make it that far.
Visually, I really enjoyed the black and white color scheme with the splashes of red to indicate things of importance (like piles of dirt, pools of blood, and things that want to kill you). But if black and white isn't your thing, and you don't enjoy that creepy Blair Witch vibe, you can adjust the color to the saturation you're comfortable with.
There is no voice acting, which I find only contributes to the atmosphere of the game, lending itself to a rather solitary and unnerving experience. There is no musical score to speak of, but rather the things you would normally hear in my neck of the woods (the birds, the breeze, and your own footsteps). A lot of this game works on audio cues. You can hear the enemies if you care to listen for them. Stealth is the name of the game (not literally... but achievements! And... health!). So I highly reccommend it.
Overall I enjoyed learning the story of these colonists. Some things, like the explosives you pick up, I have never found a use for, other than getting myself mercilessly slaughtered by every conquistador in the surrounding area. The ending, if not completely satisfying, is nevertheless what I would expect from this sort of eerie game. Definitely worth a look.