Everything before the dev contacts you is great. After that it turns into a really basic creepypasta story framework that not only manages to erase all the mystery after only a couple minutes of fantastic creeping dread but completely declaws the scary entity. There's some really great buildup and then just... poof.
There are also a couple of minor things that just don't make sense. First, I can't think of any conceivable reason this would be on a VHS tape. It seems like you just wanted a reason to have a VHS filter because that's the popular style right now. Why, if this game was never released and isn't supposed to be played by anyone but the dev, are there clearly community-run servers and clans and such? The story is totally at odds with the way you've designed the game.
Honestly, though, you don't even need the VHS filter because you completely nailed the aesthetic of early 3D, right down to what looks like vertex-based animation making the gun all wobbly and strange while it's idle. The map is sufficiently basic (maybe a little too basic, it would suck to play a real game of CTF on) and I really like how you set up the server browser.
I'd love to see the concept of "you join one of an old dead multiplayer game's last remaining servers, but things go wrong when someone- or something- else joins after you" turned into a much longer game. I love haunted video games and meta-horror like IMSCARED or Space Blaster, but the cliche and droll "this game will bring back my dead wife" story really deflated the tension and atmosphere you perfectly arranged from the first minute I spawned in. I'd suggest you show instead of tell if you decide to expand on this idea, but I'm extremely excited to see what you make next.