Cool UI, tried it on my recent flight, but for my case I could find better deal on Orbitz.

Example: WAW -> SFO (July 18, Aug 2)

IMO best: WAW -> AMS -> SFO (14h25m), SFO -> CDG -> WAW (14h5m) 1256$

Your flights are a bit cheaper, but the shortest available outbound is 18h40m.

Maybe you can tweak your algorithm to optimize for shortest flight for people willing to pay 5-10% more if that saves several hours.