The First Encounter and The Second Encounter are squished together with updated tech, new gameplay modes, new levels, and fan-favourite mods, weapons and maps.
The original shooters launched back in 2001 and 2002 respectively, and Serious Sam Classics: Revolution was started by a small dedicated group of fans.
”Serious Sam Classics: Revolution was started by a small team of dedicated fans that wanted the originals to live on for modern gamers and expand based on the community’s desire for new Serious Sam Classic content. Through Steam Early Access and Steamworks, the fan led development team plans to update some of the underlying technology and create new content, campaigns, and gameplay modes for the legendary shooter based on suggestions from the community itself.”
The group formed independent development team Alligator Pit, and right now their Serious Sam remake is available through Steam Early Access for £7.99 with 50% off for the first week. If you happen to own Serious Sam Classic: The First Encounter and The Second Encounter on Steam then Revolution is free to download.