Hello! Thank you for your post~!
To address concerns first:
The build is just a mansion demo- meaning it's just that slice of the experience showcasing only the Mansion portion of the game. The overall experience is an adventure that has you exploring Transylvania- going to towns/areas and finding what you need to enter the mansions. The demo itself only demonstrates a small portion of the whole experience~ Any additional options (dipswitches for birds for example) offered in the demo are just for demonstration purposes. Progressing in the game goes from an exploration adventure where you talk to NPCs and try to figure out what you need to do, and then when you enter a mansion it becomes more of a traditional action game with a lives system- running out of lives simply takes you to the mansion entrance. It's a hybrid of old and new~ The first mansion's design is intentionally familiar; a bit of a nod. By the time you make it to that point in the game proper, the player will have played probably a half hour of content far removed from standard CV. Plenty of checkpoints, places to explore, and things to do~ Structurally I consider the game similar to something like Link's Awakening in terms of how you progress level to level.
Being able to move past the boss is definitely not intended! I'm pretty sure when I added his intro I forgot to implement the boss boundary activation~ I'll have to look into it. Thank you for catching that!
The game has saving in churches, however there's no reason to have saving enabled in the demo since it's just the mansion~
On my Twitter I post regular videos and updates if you'd like to check it out~ Lots of different stuff to see. Here's a link to my sizzler that shows things that aren't in the demo: https://twitter.com/Programancer/status/1254133716315709449
In the end the goal is to have an experience that feels both fresh and familiar! In the end it should feel like a little bit of Castlevania, Shatterhand, Power Blade, and a whole lot of NES tropes.