- Home: https://github.com/Croteam-official/Serious-Engine
- Inspiration: Serious Sam: The First Encounter, Serious Sam: The Second Encounter
- State: mature, inactive since 2017
- Keyword: adventure, content commercial, multiplayer Online, official, original required
- Code repository: https://github.com/Croteam-official/Serious-Engine.git (@created 2016, @stars 2926, @forks 368), https://github.com/icculus/Serious-Engine.git (@add), https://github.com/tx00100xt/SeriousSamClassic.git (@add)
- Code language: C, C++
- Code license: GPL-2.0
- Developer: Robert MacGregor, SLAwww, Zi