Parker in the game and Alias's audio diary  thought it was kinda cool

have you found any easter eggs?

* not real story spoilers

Well I think the rail gun sound is exactly the same as it was in the first Red Faction game.

Also, Ultor Labs is a place you go to.  It was in the first game.

I can't say that I'm super ultra familiar with any of the locations and such from either of the first two games, although that might be because I spent more time in the multiplayer than anything else.  lol

In one of the two starting areas, can't remember if it's Parker or the area to the east of it (blanked on the name), but the Nasa Mars Rover is in one of the valleys. It shows up as a vehicle on the minimap but you can't drive it or blow it up. Happy hunting.

One of the radio transmissions you find is from Shaundi (the character in Saints Row 2).

Shaundi's radio tag is in the SE Irradiated Zone in the Badlands.
Parker is just a little bit NE of the Mohole in Badlands, in front of his hut on a hill.
Alias' radio tag is NE of the most N Heavy Metal mission in Eos, on the cliff edge.
The Mars Rover is E of the first Badlands safehouse.