This means it will come to $5 instead of $10 (or your local equivalent).
Enticingly, pre-order also come with instant beta access, so interested parties with a few quid to spare can hop into the horror today.
The 11-minute video below details a playthrough of the entire beta. It looks scary, though there are more cheap scares than I recall in the original game. The sound and visual effects often provide unearned fake out scares where you end up jumping at a high-pitched sound effect or flashing screen that have little to no bearing on the actual in-game threat. One of the beautiful things about the premise is the Slenderman's sleek, minimalist design camouflages his unsettling appearance among the tree branches, but the designers are so eager to scare you that the effects scream "OH MY GOD, SLENDERMAN!" before you have time to see him and come to that horrifying realisation yourself. He also appears too often in close-ups, rather than at a distance where he can slowly come into view.
While some of the effects are overbearing, there are still some genuine scares, which is more than I can say about most horror games (*cough* Dead Space *cough*). Plus the full game will be a much more fleshed out experience with far more locations, and the original creator of Slender: The Eight Pages, Mark Hadley, is on board, so hopefully he'll have some more spooky tricks up his sleeve.