Both the cave and mountain are gray and triangle-shaped. You can tell them apart if you just look at them individually, but it's quite hard to do quickly when playing big boards with a lot of tiles to look at.

Caves could be wider so that the silhouette is less identical to the mountains', and mountains could be covered in more snow and/or have a more distinct ring of clouds.

Deserts are basically unnoticeable when they spawn on bonus tiles. Making the desert have a lighter color could make it contrast more.

The indicators that show up above shops for fetch quests are covered by units standing on that tile. Same goes for what monsters are discovered.

Invader HUD elements block shop level and XP for smaller screen resolutions and the top-most item for even smaller screens.

Tomomo (Casual) keeping her shop discount after transforming is a bit unfair considering other transforming characters like Tomato & Mimyuu have their shop prices adjust.