The plastic tray on the bottom is very flimsy.  The platforms are very small.  But most of all the ramps are very steep for a guinea pig.  It might be ok for ferrets but in my opinion its not suitable for guinea pigs .Plus the ramps collapse very easily.  My guinea pig luckily wasnt hurt when he fell when the ramp fell.  When I placed him on a platform after he fell he just froze and wouldnt move.  The cage itself is nice itd make a nice bird cage.