I pass the lesson by opining doulingo on windows mobile apps and it did work ok. unlike doulingo for android. That's the way i pass this lesson. I think doulingo for desktop will work also.
Well "We played Mario Kart quickly before bed" has more emphasis on the manner of the playing in relation to the time before bed, that makes it more natural. "We play quickly" by itself emphasizes the action itself, which makes it seem awkward.
I still don't see it as a strange sentence. Someone asks, "How do your monopoly games only last 30 minutes?" and you respond, "I don't know. We play quickly."