This is a super cool tileset! I really like the way you use a blueish black for the outlines most places. Using a dark blue as your doorway/black color gives a cool effect. I personally think it is a bit too saturated for the types of games I tend to make. It looks more saturated than the RTP. But, that might be partially because of the simplification of the design. I like the look of the beech trees a lot better than the forest trees. I also noticed you used custom characters in the screenshots. Are you planning on making varients of the RTP characters which match the tileset?
I sort of wish there was a more desaturated and slightly darker palette with a similar detail level.
I did really like the roof and wall color tiles.
The way you did the coloring for the cliffs is super cool too.
Although, some of your large block wall tops look off with their associated wall tile.