"THE ASTRONAUTS IN THE FOREST ARE MURDERING PEOPLE!"
There's also the scene where Nelson meets Korka for the first time...he finds out that a) she's a lover of puzzles, b) she's very pretty and c) she has lots of board games for two players. So, what does Puzzle Agent Tethers say when he sees it?
It gets better: for a while her scenes are so full of innuendo, it looks like she and Nelson are the designated couple. After she invites him into her bedroom to show him something, We find out that she is a crazy conspiracy nut obsessed with Bigfoot and CIA "Mind Rays"
Nelson: I have to go. -runs out-
...Which turns into a brilliant Brick Joke if you botch up the ending puzzle.
When Nelson and Isaac try to get to the Lunar Ray, Isaac gives us this little easy-to-miss gem:
"Does your gun have a silencer?"
From the first game;
Nelson: "I miss my office. It's warm in my office. It's safe in my office. There are no maniacal gnomes or chainsaw-wielding waitresses in my office!
In 2, one of the puzzle includes solving getting some animals to the other side of a river, on a boat.
The bear will eat the wolf.
The wolf will eat the mongoose.
The mongoose will eat the snake.
The snake will eat the bear.(somehow)
After meeting the Anthropologist, Nelson is about to record his finding in his cassette. You hear a familiar click before Nelson presses the button, and assume a glitch, until you hear said Anthropologist talking into his own cassette, roughly saying what Newson was about to record.