It's really awkward the way MegaScientifical always posts worthless updates on game, like it's performing a valuable service and he's important.
On topic, this game looks like stuff like every other slender game. Also anything the recent fad of horror games has produced.
"Slender: The Eight Pages" put a sour taste in everyone's mouth because not only did it become overpopular, every little kid with a basic game engine build was out to copy it for their own glory. Slender: The Arrival should not be in the same line. They are working alongside Marble Hornets, with new character(s) never before seen. That is to say, this will be a fleshed out game. This is by no means the same dynamic Slender had: Walk around, see him, do something specific, wander away, die. They understand the problems, and they won't release the game in full until they are sure the game feels legitimate to those who play it. That is why they are also providing beta access- in that way, the wide public can also give their input and refine it to a point. I trust it will be at least an interesting play. But it should not be the monotony expected from the previous rendition.
The game does have a storyline, although it is not forced upon you. I just sent something to the founder of Blue Isle Studios, and his advice pertained to the fact the storyline would be spoiled if you were to try to convince them with anything further than the trailers.