[Update]: While a lot smaller in scope, the Serious Sam spin-off rogue-lite Tormental has now also been unleashed.

The freshly released Serious Sam:

[Update]: Serious Sam: Siberian Mayhem has now arrived, and so far it's looking like a shorter and slightly improved version of Serious Sam 4.

Developed by a group of

[Update #2]: Serious Sam: Siberian Mayhem has now arrived, and so far it's looking like a shorter and slightly improved version of Serious Sam