colony simulation game, RimWorld, optimal room size, spacious interior, mood boost, colonist comfort, 5x5 interior space, square layout, wooden walls, smooth stone floor, standing lamp, central position, plant pot, corner, artwork, steel bed, high-quality, dresser, end table, blue carpet, temperature control, vent, heater, cooler, mountain base, overhead mountain, natural light, sun lamp, 3/4 view, soft lighting, detailed texture, realistic materials, efficient space utilization, strategic game design, top-down perspective.