Mercure Salzburg City is a great hotel and I would stay again.
The staff are super friendly, the hotel is well located (only 12 - 15 mins leisurely walk from the Makartsteg Bridge that crosses the Salzach), the rooms are spacious and clean, and the beds comfortable.
The only disappointment was that the complementary bottles of water (2) in the fridge are not replaced each morning.
So regardless of a single or multiple night stay, you get the two bottles.
That doesn't make sense. If I book one night, I get the same as someone staying longer?
Mercure management team: if you are going to provide water (which I really appreciated), then please make it consistent and fair.
If I had known, I'd have bought water on my way back to the hotel on the second night. Buying your water at reception costs more than 3x the price in Spar!