: Unlocked after one playthrough, this mode adds significant replay value by including tougher enemies and new weapon upgrades. Online & Co-op Experience
The game retains the "run and gun" essence of the franchise while introducing several key additions: Serious Sam Siberian Mayhem Online
: Generally praised for having more soul and verticality than its predecessor, with a heavy emphasis on side objectives and secrets that reward exploration. : Unlocked after one playthrough, this mode adds
“The game has a tragic ending, that's a first for a Serious Sam game. Once again you can ride a mech and smash through hundreds of enemies, the coolest feature in the game.” Steam Once again you can ride a mech and
: Features significant sections involving tanks, mechs with chainsaws, and snowmobiles , though some critics feel these can disrupt the traditional pacing.
The game supports online cooperative play for the entire campaign and its expanded survival mode.
Reviewers and fans often highlight the "pure fun" vs. technical shortcomings: