We enjoyed a 7 day cruise to Norway (with a stop at Gothenburg).
The ship's crew is very friendly and all did their utmost to make our vacation easy, interesting and fun.
Of course the negatives are usually the same: the wifi is terrible and the ship's shore excursions are wildly overpriced. We avoided both as much as possible. Recommendations we gathered here and on Trip Advisor were very helpful in finding comparable (or superior) experiences at 1/3 the ship pricing.
We went for a long walk on our own in the hills and lakes behind the town. This was exceptionally beautiful and we enjoyed meeting some local residents out enjoying this park on their own too.
Sorry Gothenburg. Not much to see here.