Old Man Murray also helped to launch Croatian developer Croteam's Serious Sam, which originally had been intended as a tech demo for the Serious Engine. I believe it was Erik who wrote a review ranting about the games greatness, bringing the demo much attention, and inspiring Croteam to extend and publish the demo as a budget game.

Serious Sam is a return to the frantic, hundreds-of-enemies-on-the-screen-at-once-oh-my-god, gameplay the likes of which hadn't been seen since Doom. The switch to true 3D never allowed the hordes of enemies to be quite that impressive. Serious Sam fixed that, and the game ran quite well on the mid- and low-end gaming system of its day. The game's sequel, The Second Encounter, was released in the First Quarter of 2002.

An easter egg in Serious Sam (in the first level, if you walk off the ramp and around the corner, back behind the pillars, and open the door) results in a group of big-headed Serious developers chanting "Old Man Murray" and various other "thank you"s.