A good cross country runner could get a decent lead in the early stages, I think it's like about 5 or 6 tough cross country without there being much in the way of obstacles.
Then you do two laps of the assault course type bit which involves lots of water and stuff, guess it's a bit like a military style course but not that 'strength' orientated because they like everyone to be able to manage the stuff.
There are bits that involve getting fully submerged under a bridge and scrambled through and a lot of wading waste deep for 50 metres at a time or so. Super muddy too.