The whale sprite is wonderfully illustrated. A shame that its detail and style does not match the rest of the world, however, this is hardly a drawback of the game.
I find issue with the use of symbols in the "build" menu. Consider that signifiers should either: immitate what they are meant to signify, have a relationship with the subject being signified that is determined through sociocultural consensus, or have a sort of causal connection to the subject being signified.
Applying this knowledge, one might see how the "Octopus" symbol is easy to understand for most readers. However, they might notice that the second row of two symbols is difficult to decipher without additional information (for example, language/text). Consider making sure that readers and players can access the game and it's newly created information equally and easily. Of course, a player can use trial and error to observe changes to the game from selecting different symbols, though I wouldn't consider that more efficient and accessible than naming original symbols first and foremost.