First off: This wall looks like two differently-coloured textures. Note that the lightmap resolution is set to default (16), so it isn't caused by that. Hammer view: They are different textures, though. One of them is the normal texture (the one that appears strangely yellow in-game), and the other has dirt along the bottom. Next up: These grates don't appear at all. They're nodraw brushes with the grate texture applied only on visible sides. They're also func_detailed and grouped with the metal support beams. Hammer view: Finally: Now, this is bizarre. This grate appears culled towards both edges. However, not only does it appear correctly in Hammer, it also appears fine on the bottom! Again, this grate is func_detailed and grouped with the rest of the bridge. If anyone has the answers to any of these oddities, it would be appreciated. Thanks!