Ha! Ok, I've beaten the game now, and... I was wrong about a lot of things in my last comment :D
I maintain that Healing Potion, and Fireblast, and indeed most of the 2AP cards are very powerful, if I can hang onto 2AP and the card for long enough to play them. Relying on that means that the most useful card in my deck is probably Rest.
I haven't tried the shield-heavy strategy with Shields Up, Shield Bash, and Transmute Shields yet. It looks like it'll be tricky to get going. Too slow to end the game on turn 2 the way Fireblast does. But it clogs my deck with unplayable Shields so it's not a good slow-game plan either.
I found a completely useless infinite loop where I play the 0-cost card that mimics whatever's on top of their graveyard, and that card in turn draws the top card of my graveyard, which of course is the one I just played. What a convoluted way of doing nothing at all!
... anyway! This game is lovely. A bit of graphical polish and some sound effects are all it needs.