Can I remove parquet flooring adhesive by using a heat gun?
I'd advise against using heat. Last week I removed a parquet floor from my living room that had been stuck down with bitumen. After trial and error I found the best technique was to use a hammer and chisel to prise the tiles up, leaving just the bitumen coating on the floorboards. I then paid a guy to sand up the bitumen with a large industrial sander using very rough sanding paper. It took him about half a day and the floorboards now look great. (Make sure you use very rough paper and a powerful machine - if the paper isn't rough enough, the bitumen just gums it up.)

I did try a heat approach but this just melted the bitumen, making it sticky and even harder to remove. I also tried to use solvents, which had the same effect.