YouTube - Serious Sam TFE: RAY TRACED - Release Trailer by sultim_t.
YouTube - Serious Sam Gets A Fully Ray Traced Upgrade! Graphics Comparison, Performance + More by Digital Foundry.
YouTube - Serious Sam 4's Incredible Fan-Made Remaster by FrameRater.
Seriously! (only file archive, rest is on Discord).
GitHub - Croteam-official/Serious-Engine official open-source GPL-2.0 licensed release of Serious game engine.
GitHub - icculus/Serious-Engine
GitHub - ptitSeb/Serious-Engine A port to the OpenPandora (and working fine on plain Linux) of the open source version of a game engine developed by Croteam for the classic Serious Sam games. Status: Working (for both FE and SE).
GitHub - brynet/Serious-Engine A port to OpenBSD of the open source version of a game engine developed by Croteam for the classic Serious Sam games.
GitHub - tx00100xt/SeriousSamClassic Open source game engine version developed by Croteam for Serious Sam Classic (Windows, Linux, FreeBSD, OpenBSD, NetBSD, macOS, Raspberry Pi OS). Based on GitHub - Croteam-official/Serious-Engine and linux port GitHub - icculus/Serious-Engine.
GitHub - tx00100xt/SeriousSamClassic-VK Open source game engine version developed by Croteam for Serious Sam Classic with Vulkan support (Windows, Linux, FreeBSD, macOS, Raspberry Pi OS). Based on GitHub - sultim-t/Serious-Engine-Vk and linux port GitHub - icculus/Serious-Engine.
GitHub - sultim-t/Serious-Engine-RT Serious Engine: Ray Traced. Real-time path tracing support for Serious Engine 1.10.
GitHub - tx00100xt also has several Serious Sam: The First Encounter, and Serious Sam: The Second Encounter mods.