My first 3D game, I used Unity 3D tutorial assets to make a game with 10 unique levels.
I hope you enjoy.
I followed Unity's tutorial through then Used prefabs to make the levels modular. I used the mobile bumped specular material on most of the decor so it would be less processor heavy. Unity 3D is really an awesome game engine. Let me know if you have any other questions about the game and any aspects of its creation.
Stealth escape 3D by 5StarGames
Google Play Link