I think these are ok overall, but there are a couple of things I note:
1) The waterfall: Sky is overexposed and right side is underexposed. Cropping the picture to show less of the right-hand side forest and also cut a little of the sky would improve the image. During the shooting you could have used bracketing and then merged the exposures afterwards to get good alround exposure (if you had a tripod).
2) The cat: Love it, espcially the glass-blue eyes. Looks like a mean fellow...but then again your other cat-poses sort of contradict that, hehe.
3) The tree: I've previously asked "
can logs be interesting", I'm still not convinced. At least the background should be more blurry to emphasize the tree in the front.
4) The Rocks: Hmmm....yes and no...I think you could have done more with the foot, i.e. used it somehow. As it stands now there's nothing leading the eye anywhere....a more prominent foot might have created some foreground interest....hmmm
5) The flower: Generally ok, but perhaps a polarizer would have given it deeper colors, seems like the focus is not on the yellow pollen...maybe it should have been...depends on the "message".