Isometric 3D models in retro games often have weird shading because older hardware lacked dynamic lighting, so static, simple shading clashed with the fixed isometric perspective.
Older systems used flat/dithered shading (no real-time changes), so shadows/highlights stayed fixed even as the isometric angle revealed different parts of the model—causing inconsistent, unnatural lighting when objects overlapped or had uneven surfaces.
For retro-style isometric games, use intentional flat shading or a limited palette to embrace the classic vibe—avoid modern shading that feels mismatched.