Far as I remember, this used to be the online side of the secret shop for The International (Dota 2), then generalized a bit to sell Portal t-shirts and whatever. The company that actually ran it changed hands & names a couple times until Goodsmile bought it, and I doubt Valve care too much to find another vendor at this point.

Terry Gilliam's Brazil always does it for me. Depends heavily on which version you watch though, they're polarizing enough that you can play emotional Russian roulette with both versions.

Yeah, I think back when I did those acheevos it ended up being a mix of necro, mesmer, and maybe guardian, even though I'd rather play engie. Can count on it coming back next year if you don't clear it all this time around, though.

If you're absolutely stuck with just core engineer and rifle, try equipping Elixir Gun and just 111-ing it down with Tranquilizer Dart. It's not the strongest thing around, but it's one of the few autoattacks engie has that doesn't pierce, bounce, or explode. Make sure you don't have any traits like Aim-Assisted Rocket that trigger yet more AoEs.

Here's a positive: cigarettes make a great mosquito repellent, because nicotine is a natural insecticide and the smoke/odor repels them. It also repels girlfriends and other humans, but still.