OGS Engine is a GoldSrc game engine reimplementation using only original id Tech 2 (Quake/Quake 2) engine (and its forks) sources with some bits from the id Tech 3 engine and no reverse-engineered code
Updated the client dll view code to use client-side simulated/predicted origin (QW/GS approach) instead of (client) entity (world in our case) origin (NetQuake approach) for view origin and now it's actually possible to see the map.
Also, partially fixed/restored client-side input code (inputw32/in_win) and now you also able to look around (again), but it's still buggy.
As you can see, something really bad happened with the poor render and now it can't even render the map properly (looks like some frustum issues but haven't investigated that much yet).
The palette is still fixed for map textures, but the code for the per-texture palette is already in, just need to fully integrate and fix it.
Map: Moddb.com