Happy 15th anniversary to Serious Sam, though the official birthday of the release of Croteam's first-person shooter was actually yesterday. The Croteam website has a celebration of the news, discussing the project and offering visual aids such as this previously released video showing an early beta version of the game. They also now offer Steam Community -- Group Announcements -- Serious Sam 15th anniversary trading cards on Steam and a sale on the series. Here's word:

After receiving hundreds of emails per week from gamers all over the world who loved the demo, with our batteries fully replenished and secured funding from GoD, we went on to finish our first Serious Sam game. To be honest, The First Encounter was (and still is) one of our dearest games, in which we poured our hearts, soul, sweat, and tears. It took us years to develop it, but on 21st of March 2001, the wait was finally over, our baby was released in stores worldwide. It had a great reception, everyone loved the crazy over-the-top gameplay combined with beautiful visual and audio presentation, and we were really relieved once first (positive) comments started pouring in. And best of all, it won Gamespot’s prestigious Game of the Year award, as well as numerous other awards and praises from the gaming press and community.