Oh, awesome. :D I always love seeing LPs of Demon! If they're on YouTube, I can link them on the devblog too. But, the video you linked is currently private :P
Re: Unlockable relics, I've thought about it a little! If I did do unlockables with the starter relics, I'd probably handle it like the Demonic Compendium: you'd have the option of just playing with everything, whether you had them unlocked or not, or you could run it with just what you'd unlocked. :) I'm usually in the "I want all the gameplay options now" camp myself, but I know there are definitely folks who like unlock-based systems too, because it makes things simpler for them while they're still learning by reducing the options that need to be considered, because it gives other goals to shoot for during gameplay, or both.
Cool! :D I'll check it out when I get home tonight!
In the current version, there are over 110 different recruitable demons (this does not include variants due to random traits that can modify them.) Red Caps are a bit tough to convince to join you, but their free action self Accuracy buff and early ranged attack (even if it is only throwing rocks) are kinda handy.