We trained for spear throw, rope climb, wall walk, angled wall walk so those werent bad but messed up a lot of people. Sandbag and 1k bucket carry were tough but anyone can do those... its just a grip wear out exercise. We also trained on rope pull and monkey bars, so those werent bad at all. Tire flips were heavier than we expected. Atlas ball lift was not bad at all. 100 yard barbwire crawl wasnt bad if u were ok taking your time. Our training was aimed at avoiding burpees... but if u dont do punishment for failed obstacles it doesnt matter. (We did all our burpees and had trained with burpees).
I specifically failed the 3 obstacles with "twisters" and one with rings/bar/rings. Twister is so tough, particularly during a race after a bunch of running and grip stuff. I also failed monkey bars on a rope, but was more trying to conserve energy and figured 30 burpees was easier than that obstacle.