If you're struggling and want an easier but still rewarding experience, play with either Soul Sapper or Gang of Graverobbers as your mini-boss. 

Both these mini-bosses make all cards cost 2, which allows you to play more potent higher-cost cards for less.  Steeling enough resolve to compensate is a breeze. Just play your 1-cost cards as perils at the start of the game. There is no downside for playing perils this way, since all perils on 1-cost cards are only 1 power.

You've made me realise the current draft pdf of cards has a typo! Soul Sapper is meant to have a different effect ("Willlpower cards have -1").

But otherwise, this is good advice with Gang of Grave robbers!