For what it's worth, the full game has stage select that allows you to start from any stage you've reached so far. Extra continues can be earned as well, however they're still limited.
Recent community posts
We ultimately came to a decision that a new, more distinct name would go a long way in helping with the game's recognizability now that we're making a commercial release. "Final boss" wasn't exactly google-friendly for people trying to find information about the game after all.