Really cool grassland level. The castle/ruins graphics were impressive and there were some nicely hidden secrets. I have two suggestions.
The coins are somewhat misleading since they make it look like there might be a secret down that pit.
I know this is the shadow realm, but I think this part is still too spammy. This level of difficulty would probably be fine in any other world, but for the sake of being the first world, I think it would be better if it was slightly nerfed.