The Art style and design I’m going for in this world is concrete brutalism mixed with sci-fi decorations and items.

Architecture:

• Living Quarters 
• Garage  
• Prison 
• Portal gate 
• Altar
• Secret Room

Decorations:

• Locker 
• Workbench 
• Barrel 
• Skull trophies 
• Battery packs 
• Bed 
• TV 
• Table
• Handcuffs
• Storage bins
• Chairs
• Buttons

Concept Art

Modeled Preview

Reference