"Mercure Hotel Dortmund City" is basically not a very bad hotel, but I fear they believe they act 2 or 3 classes higher as they actually are. The room is fine, but it's clear that there hasn't been invested in a long time. Old fashioned (dusty) carpet, old bathroom, no points for chargers anywhere close to the bed, etc. The bar is also very minimal and not especially attractive, allthough prices where amongst the highest I've seen in Germany. In the morning I was surprised by a breakfast charge of 18 euro. I knew breakfast wouldn't be included, but this was definitely not worth it. Again, not a bad breakfast buffet, but the cost doesn't match the actual offering. Finally (but something they can't really help I guess) is the awkward entrance: if you've never been at this hotel I'll probably take you 15mins to find the entrance. The building has Mercure written on it everywhere, but it's not clear where to park and the entrance is a small door around a corner, from where you have to take the elevator to the 3rd floor to find the reception... and the neighbourhood isn't really inviting for walking around in suit with a laptop and travel suitcase...
If they lower prices (e.g. single room for a weeknight at 60eur and a breakfast for 12eur), I would consider visiting again. As said, it wasn't "bad", just not worth what I had to pay.