A platformer/visual novel with each mini level + boss touching on a different type of ecological destruction seems a really good idea! Though the scope is quite large, the idea has plenty of flexibility to have more/less levels + characters based on your capacity as you continue - though I'd say maybe it'd be worth thinking of upgrades + item variety as fun stretch goals to include at the end rather than integral elements. Your mood board of pixel art inspirations makes me excited to see the game develop, and the selected theme of presenting animal's perspectives will be really interesting; I think challenging anthropocentric approaches to climate change is an important point!
Good luck, I can't wait to see what you come up with for the next sprint 😊