The rotating room idea is clever, and I thought it was cool when the room wasn't just a square either, when the room had more sides and rotated differently (not 90 degrees). The level design in general was really good.
The graphics are nice and crisp, and the UI/title screen looks really polished. It feels clean right from the start. I also like the extra mechanics, like the portal and being able to flip the spin direction. Small additions, but they added just enough depth without overcomplicating it.
Short, but it does exactly what it sets out to do. Solid little entry.