OR2SDX is Monta Vista Linux Kernel with XFree, I believe it OpenGL based, needs a certian nvidia linux driver, otherwise you get shader errors, it needs an older kernel anyway (like VF5/VT3) to run as they changed the com port naming conventions from /dev/ttyS0 to /dev/tts/0
Lindbergh Blue is Windows XP Embedded and even then they use a mix of DirectX and freeglut/openGL - the Windows/Linux code is pretty much identical..
Ghost Squad Evo like OR2SDX was just a recompile of the Chihiro version, GFX where a 1:1 recycled for sure. Chihiro was discontinued, and I am guessing there was still demand for Ghost Squad at the time (it was the biggest shooter in 2005).
Games like primeval hunt and 2spicy (and even Rambo) arep pretty bad, I've seen better 3D on a freeware games - so I am 99% sure these where not done by seasoned development teams, or maybe Sega did not do the same level of API/LIBs that they had for say Dreamcast development.
On the plus side I love the Lindbergh, and still has many future classics and obviously will have the last version of Virtua Fighter, although I doubt I'll ever see it..