Game seems really cool, 1 suggestion, the game is really laggy, one easy possible way to fix it is to use occlusion culling, if you are using unity you can find it in the documentations, or a youtube video, its like 5 mins, very easy. This way it will only draw objects in front of the camera.
Another thing you can try is to bake the lights so the computer will not spend time on baking them in real time.
Otherwise, its a really cool game well done.
If you have time check mine too :)