That's pretty cool looking, reminds me of a dorm I lived in (hexagonal rooms).
Unfortunately it has pretty serious 'trapping' issues. In general a play structure should not have V shapes in it, particularly acute ones. Acute V's are abundant on this fort. V's are dangerous because a head or limb can be caught in them with the body weight pulling down. Obviously the worst case is strangulation, but lesser injuries can result as well. Another rule for avoiding 'trapping' is that all openings should be less than 3.5" or greater than 9". So that heads and bodies cannot pass through or heads can freely pass.
And, please, i'm not freaking out about it and sneaking over to their house to tear the thing down in the dead of night. Just recommending that future builders do 30 minutes of research into structure safety (google 'play structure safety guidelines') and incorporate it into their designs.