This is where the kitchen is going to be. Where my husband is will be counter top at that height. with a big wide counter top to sit under. on the back wall double door fridge a metre gap. 2 wall ovens then a sliding door where the ladder is. A scullery. Behind my husband to the side of him a sink the cooker then space. Where the big flat plank is on the ground (ish) will be the movable island. you can see a taster of the stone wall which will be on both sides of the entrance hallway, the flooring will look very similar to this http://carpetdiscounters.co.nz/product.aspx?product_id=441 . You may note the steel next to my husband on that side. it also needs to be treated. Thank you very much

What is the rest of the house like? Would you like overflow sleeping areas or more storage? If you can't raise the floor (and the ceiling?) you might consider building in some comfortable seating/storage areas that use pillows/cushions and play up the multi-level idea and make it look intentional. Similar in concept to the stepped couch.

The all black kitchen looks scary as. Maybe because there's no lightness in there at all.

You are correct the place does and always will look a bit sparse when you only have blinds. The question with curtains is sometimes dependant on what climate you live in and I am not sure where you are so I am going to say. If you need curtains for heat go for a quality curtain to the floor with a fabric that is not stiff (as I discovered I now own after buying curtains off line for my spare rooms). The expensive curtains I brought for my living room have a softer texture and hang so much nicer. As I need Curtains / Roman blinds for heat I have backing fabric etc on the expensive made to measure ones, where as the cheaper ones are just thermals. If you only want to add a curtain for looks and do not require it for heat I would recommend going with a lovely sheer / half see through fabric that drapes really well, this will add a point of interest and you can colour match or add a loved colour to a bare - white on white - cream on cream - colour scheme.