Shard System = a better soul system, Dullahan Shard OP.
Backdash can be canceled with down, only this time it's a faster option of travel (Speedrun senses tingling)
Enemies are great, especially Amy, because it's name it Amy.
Speaking of Enemies..... Only gripe is that the DS formula is being repeated here, After playing some Shantae: Pirate's Curse, I got used to faster, more aggressive enemies, I won't put it past the demo because it is a demo, only to demonstrate what's to come.
Boss is... underwhelming, Don't get me wrong it's good. I'm just tired of the Hit/Dodge on Sponge bosses of the DS games, needs some AoS balancing.
Graphics, 9.5/10, The Models and environment looks rather immersive, Only nit-pick is that weird overhead light that makes Miriam both abnormally brighter than the stage and casts an out of place shadow.
As for a Demo, well.... I LOVE demos it's a great way to invest enough into a game to know if you'll like it.... Unless it's a bad demo (LoS 360 demo, the PC demo made up for it for giving you the first 3 stages)