Most skills are a bit garbage going into after heroic play, but i found serpintine arrow and incendiary to be very strong,obv paired up with the ranged passives and the 3 90second buffs.
Chests tombs and loot drops are for most part pointless, look out for the traveling salesvampire Nya, she sells 5 uniques which some can be heroic (I dont think she summons on normal setting), if you do want to loot a bit , try the nosferatus on lvl 3 of vampire city, great exp/gold and 3 equips.
Cleared on Hard mode, really enjoyed it despite the mild targeting and lighting complaints (which didnt affect gameplay after the first 10 mins).
Great job dev, looking forward to this game as a series.
The save points are in the worst places, no clear idea how wall climb works when you first get it, and inverted jumping with buggy controls 1/5 looks nice has charm to it, but gameplay and inverted slopes lets it down greatly.