Thanks! I have considered adding an easter egg with the original sprites, and might do it. We'll see...
Enemy respawning isn't perfect yet, still working on perfecting that. The abilities in the demo will not be there in the final game, but will be spread out across the different locations. The only ability that'll stay where it is now is dive. We haven't programmed death yet to make it easier for testing, might be one of the last things we do actually.