Kill the Catfish.

Kill a demon with fire.

Install a modification of each category on a single weapon.

After running out of filters in a hazard zone, craft a new one while suffocating.

Find a tune on the radio.

Complete the MOSCOW level.

Patch the Gasmask.

Breathe some wind into your ocarina, my skyward princess!

The truth was out there all along!

You reached a higher state of mind. Or at least some peace and quiet.

Don't feed the animals! Or do, they're adorable.

Again? Keep track of your kids!

Helltower? More like hello-from-up-here-tower!