Marble HornetsI suppose it's not really a video game creepypasta so much as it is a meme thing, but still, it fits the general basis for these stories. You must watch all the episodes from #1 to #34 until they make more. Also, watch the totheark videos as well.
I'm sure many of the older users remember this creepypasta, and it'll scare you stuffless. It will take you an excess of one hour to read, though.
its fun and entertainingnot scary
http://creepypasta.wikia.com/wiki/TEH_DAY_OF_ALL_TEH_BLODnot videogaming, but damn hilarious.
Clock Tower dont need a CP creepy as he- already
http://creepypasta.wikia.com/wiki/A_Fresh_Start