your tiles looks nice so far. i wonder why you did constrain yourselves so much, since with 8x8 it will be somewhat harder to create something recognizable. i think good contrast between the elements (background and player, for example) is imperative.
so what i would like to see to give some feedback is two things for now:
- put your sprites on your background tiles, to see if they are recognizable in the "use case"
- show us your sprites animated (on a plain background for starters), to see how it works out then. one can't tell that reliably from looking at the frames singularly.
- as a third point (I know, I said two ) put your sprites animated on your background tiles
looking at your still frames, my prediction is, that it won't work out exactly well, at least for some of them, since on the walk upwards you only changed the brightness of the leg-pixels without really "moving" something.
but let's verify that in action