I apologize about not responding Juni, but it was somewhat hard for me to develop a bit of feedback without being destructive.
8bit tileset:
Good points:
Stone cat was fairly well done. (Perhaps stone should be the main theme of this tileset? I often find myself being fair at one tileset type and stink at the rest.)
Bad points:
Not really enough for me to criticize.
Seemed to lack a couple extra details upon the terrain. (As far as I have seen, terrain usually has three colors, so that may be a rule of thumb to incorporate for tileset making.)
Stone tablet seemed to lack a bit more detail. (One color more would probably do the trick, or even an outline will suffice.)
Advice:
Possibly add a bit more detail to the ground tiles. (Like a darker green or some similar conclusion.)
More tiles could be used. (1x3 of ground, 3x1 of ground, and even slopes of different grades if stumped on what to add.)
Blood tileset:
I'm afraid I honorably can not review this tileset... might need more blood spatter.
For first try, you've got the basics down, and don't be afraid to put in something ridiculous in a tileset. If it works out, then presto!