I was a little concerned about the dark flooring as well but so far it hasn't been an issue. I always check it periodically. There is good ventilation underneath from the decking and there is always a patch of shade somewhere since the top is solid fabric. I live in a coastal town in Northern California so 85 degrees is a HOT day here. I would love to add some sort of substrate, climbing tree, soaking pool, more hides, etc, but I have to break it down every day... Not everyone in the household appreciates the playpen taking up deck space!