I like the concrete bloc walls. They are becoming quite fashionable today. I'd keep them in the natural concrete color or if they have been painted, a color paint that resembles concrete. The concrete walls give a hard and cold impression so I'd choose wood flooring for the floors. The combination of a warm wood on the floor and hard, cold concrete on the walls is a nice one. Brighten the space with colorful modern art.

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I would balance the fridge cabinet wall by having the fridge centred between two narrower pantry cabinets as it currently feels far to heavy for your space. Alternatively, I would recommend having a narrow pantry on the left of the fridge with a full height cabinet with counter on the right with an upper cabinet above. This would help your space feel larger.

I never love open shelving in a modern kitchen they are dust and grease traps but I would hang horizontal glass front cabinets and paint that wall some awesome color ,run your backsplash up to bottom of window all across. If you have space make the island top larger and paint out the other wall of cabinets to match main ones. The island top could be something much different than the others