Okey just a quick view from the screenshots.
Tropical Resort ACT2.
- Those KOF dudes sprites clash with the Env coloring maybe darker them a bit and give them a slighty purple coloring could help.
Planet Wisp ACT 1,2,3.
- The mist trasparency make it look too glowy sugest use an Addalpha of around 200 or 180 rather than just "Add" to make it more trasparent and less glowing.
Aquarium Park ACT 1,2,3.
- Everything clash compared to those chinese building coloring and spritewise due being of a higher quality than the rest of the sprites used on the stage also imo reflection would fite more rater than shadow.
Some stages.
- these would look better with a slighty coloring overlay such the night stages having a dark blue or black overlay and the sunset stages having a orange overlay imo.
Gona give them a try later cuz the concepts looks nice but thats what i see from the screenshots himself.