Upstairs wooden floor, covered in glue after removing tiles. Advice?
You gotta do what you gotta do. But before you knuckle under and decide to start ripping out the floor boards do a little investigation. If the floor boards extend out under the lower plate of the wall (especially load bearing walls) you will want to reconsider outright removal as remediation at the walls can be very problematic. Get yourself a good chisel or two, a heavy hammer and some ear protection and go at it. It often takes good old labor and hours of time to achieve what you want.

If the glue is hard and dry it is sometimes not that problematic to remove with wide sharp chisel to get the biggest parts off and then use a scraper to remove the rest. A heavy duty floor sander can also be used to remove dried glue but often the heat generated by sanding will soften the glue to the point that it just gums up the heavy grit sand paper.