Ooh, a dinosaur boss would be really cool! I don't think I have a dinosaur asset (yet) but I do have other assets that I haven't used and I'm planning to add to the game.
Having closure to a level makes sense, one of the big features I'm planning to add soon is a "campaign/story" mode, where each level is more directed and meaningful, and there'll be more closure for each stage, compared to the current mode (which would remain as a "classic/endless" mode) where it's wave after wave of enemies :)
Thanks for the wishlist, and I'm really happy that you and your daughter enjoyed the game!