Blender Game not rendering models correctly, normals recalculated and flipped, The model looks fine in blender (texture, material, and render),
but when I run my app the parts of the model don't show.

The normals have been recalculated and flipped many times (sometimes only affected areas too) and all doubles are removed yet nothing seems to change.

By playing around with settings I've been able to get better and worse results, here's the best result I've gotten:



(doesn't seem to be changed by culling settings) and here are all my settings:

Blender Games issue

All textures and materials have the same setting applied, the missing bits have the same textures and materials as the non-missing bits
I figured out what was going on after a few hours of trial and error, the issue was that the faces that weren't displaying had more than 4 vertices, once I triangulated the faces everything worked fine. The issue with some other textures disappearing depending on different culling and normal settings was due to the object being scaled in the negatives on the y-axis, blender doesn't like that apparently.