That’s not surprising. Half-Life 0.52 used a graphics translator (a wrapper) that converted OpenGL commands into Glide. This was necessary because the popular 3D accelerator at the time, Voodoo, did not support OpenGL commands - only Glide. If you don’t run the game through nGlide (or another compatible translator), artifacts will appear. For example, if you run the game directly or delete the translator’s DLL file (such as opengl32.dll, which performs the translation), visual glitches will occur: weapons, bullets, or grenades may "clip into walls", or textures may be applied incorrectly.