Berlin hidden restaurants and nightlife spots

I'll be in Berlin for a weekend (Dec Protected content another Internations friend and we'd like to explore some "hidden" restaurants (meaning places you won't find if you haven't been told it's there as there isn't much indicating it's a restaurant from the outside). Same thing applies to bars or nightlife spots.

On the other hand, I would welcome any opinions on the following hotels:
- Bleibtreu Hotel (Charlottenburg)
- Adele Design hotel (Friedrichshain)
- Angleterre Hotel (in Kreuzberg)

Looking forward to interacting with the Berlin community!