thanks for playing and the kind words!
something to differentiate stage numbers [...] Possibly add different backgrounds & music to the worlds?
for sure. i might even extend the zones somewhat
The font was hard to read in some places. D & O were very similar at a glance.
thanks for letting me know, i think you're right. i'll work on it
There is a bunch of terminology that isn't really explained on skills
yeah, i'm still figuring out by what means i want to show this to the player
there were moments in the final battle where there would be one or two cards left and both of us were just end turn-ing repeatedly because we couldn't get a suitable card
the intended design is that cyan and gray 
skills would benefit you in that situation - cyan by making it easier for you to draw/pick up cards and gray by giving you benefits when you end turn/take no action. optimally, i'd want players to have to consider that situation when making their build