Development work on Serious Sam began by Croteam, leading up to the first game's creation and eventual release.
An HD remake of Serious Sam: The First Encounter was released, updating the game with improved graphics and modern features.
Serious Sam discovers a time hole left open by Mental, the alien overlord, enabling travel back to the 22nd century Earth.
Mental launches an invasion on Earth with his monstrous armies, laying waste to human civilization.
Serious Sam is deployed as humanity's last hope to travel back to the 22nd century to stop Mental's invasion at its source.
Using the time hole, Serious Sam lands in a version of ancient Egypt occupied by Mental's forces and begins his assault.
Sam fights through hordes of enemies including Beheaded Kamikazes, Kleers, and Gnaar in various ancient sites such as temples and deserts.
Serious Sam destroys several key fortresses and enemy bases destabilizing Mental's grip on this timeline.
A notable battle occurs where Sam wipes out a large group of the deadly Kleer Skeletons blocking his advance.
Serious Sam reaches Mental's inner sanctum and defeats the last remaining forces to secure the fate of Earth.
After defeating Mental's forces, the time hole is stabilized to prevent further temporal invasions.
Following Serious Sam's success, Earth begins to rebuild from the devastation of the invasion.
