there is a missing bridge for pedestrians and cycleway which is a level lower then the car bridge "rötistrasse".

It is between Kreuzackerquai to Ritterquai.

Unable to answer "Do you have to pay to use this restroom?" for osm.org/node/8558238229 via StreetComplete 38.1:

Doesn't exist above ground

Die Bürenstrasse und die Solothurnstrasse beginnen hier.

Unable to answer "What kind of building is this?" for osm.org/way/188311205 via StreetComplete 38.1:

Doesn't exist

Unable to answer "What are the opening hours of Wysion (Wine Shop)?" for osm.org/node/1823118046 via StreetComplete 34.2:

Weltladen Solothurn

North-most track seems finished, according to https://youtu.be/tBpst_dH_2Q?t=4305

BAR XONI

"Didn't see it and site doesn't work"
The place has gone or never existed. This is an auto-generated note from MAPS.ME application: a user reports a POI that is visible on a map (which can be outdated), but cannot be found on the ground.
POI name: suppen & baked potatoes
POI types: amenity-restaurant
OSM data version: 2017-06-09T16:24:09Z
#mapsme

motor vehicles allowed? Pls also refer to http://www.mapdust.com/detail/3160495

Meines Wissens besteht der hier eingezeichnete Poller nicht mehr. (Jedenfalls konnte ich kürzlich ganz legal mit dem PW von der Rötibrücke via Rosenweg - Ritterquai auf den Klosterplatz fahren.)