On the one hand, I'm extremely excited to see an Adult Swim/Valve mix that doesn't just involve a sign-up sheet and a hat.
The claymation is also a nice touch. But this feels more like Adult Swim saying, "Hey, here's a thing that sorta looks like a thing that you play online sometimes", rather than actually doing a proper spoof off of Team Fortress 2. It's kinda silly, maybe even kinda funny, but all around not the kind of witty and on the nose humour you may have expected from such a collaboration.
But then again... Hey! Here's a thing that sorta looks like a Team Fortress 2 thing, and that's neat!