So there's this game called Paradox Embrace which has some ad space on the front page, and has medals associated with it. Three of those medals are for finishing levels quickly: Speedy Runner is for doing levels 1-5 in under 20 minutes, Spacetime Traveller is for levels 6-9 in under 20 minutes, and Paradox Embracer is for doing the whole game in under 19 minutes.
My best time for the game was a little over 17 minutes, and this afternoon I cranked the quality down to low and gave it another go. Man, did it ever make a difference! I now believe all my level times are within 1 or 2 seconds of being optimal, as listed below. My total game time is down from over 17 minutes to 16:00 even.
So this post is partly me bragging about my times, and partly me giving some advice: if you're struggling with your level times for the speed run medals, play this game on low quality even if you think you're getting proper performance at high; you may be pleasantly surprised.