Floor plan UG-EG - Sloping site

very good! Only the windows on the south side are way too small. Now please add a shower in the bathroom so the oldies can live upstairs later. Maybe rotate the stairs (depending on what should be upstairs or downstairs) and give the bathroom more depth.

Plan a path around the house for wheelbarrow, hand truck, lawn mower, and the like. And think again about a direct access from hallway to garden. In the basement, you have large rooms where you can take a bit. For example, if you’re mucking around in the garden in bad weather, you can take off muddy shoes in the hallway and then go sock-footed to the bathroom, etc. Nobody wants to put on damp shoes after 10 minutes. Or the kids (yours and visiting children) don’t storm through the bathroom into the house. I’d rather have the sand dunes in the hallway than in front of the shower. In the utility room, I would provide a sink for hand washing and to rinse out a glass now and then. Depending on how the north garden is used, I could imagine that two wine glasses, a Dolce Gusto, or something similar might find their place in the basement.

And think again about a direct access hallway - garden. In the basement you have large rooms where you can cut off something.

Yes, the bathroom is huge and the little son doesn’t even notice if it’s “only” 18 instead of 20 sqm or so:

And I would swap the dressing room/bedroom...

Normally that would make more sense. But here the bedroom then has no window because it is built into the hillside. I would probably forgo the extra hallway because you can simply walk around the outside on both sides of the house. But in any case I would plan a patio door for the son. Maybe on the ground floor the stairs could be swapped with the bathroom and thereby have the possibility to expand the bathroom to include a shower (at the expense of the study). In the basement there would then be a smaller utility room and north of the stairs an additional storage room.

The bedroom is more practical and nicer in the proposal from if you leave out the small wardrobe unit. You would then have over 4 meters of wardrobe space available and additionally a nice large bedroom. In the middle, you could also put a dresser island as additional storage and surface area.