i think i've found the most broken build so far (probably not the only one since this game is kind of unbalanced for certain builds like bleed that suck ass)
best part is that it can clear both normal and hard with 0 carryover perks (besides merchant at lv 5 in hard mode)
it's a super acceleration deck:
-4xchill (the 0 cost weaken attack)
-4xhatred (the temporary +3 buff)
-3 or 4 pot of greed draw 3 card
-1 shield card (choose between haste, big wall, or the starter one)
the core of the deck, basically playing buffed chills forever
remove every starter attack and shield as soon as you can so there's no rng on what you get and upgrade the draw 3's into draw 4's
you can basically hatred- hatred -chill- chill-draw 4 3 times every round, without taking into account artifacts or other cards.
you have an infinite turn if you're lucky and get the artifact that gives you a draw with every lust spell, and quick shot (0 lust cost, upgraded is not extinct, draws a card and deals damage) but even without the combo, you can kill everything except those goblins that buff their their attack with every hit, which you kill slowly until he's on 35ish hp and you infinite him down.
extra broken points if you get necromancer's staff that gives you 3 life drain, now you're immortal as well, although i recommend getting rid of 1 of the 3 life drains for better rng.
final combo to break the deck:
double penetration (repeats mana skill)
-metallize (if you need shield)
-amplify (if you need killing beefy targets)
-that one card that costs 0 and gives you mana and draws.
with a minimum of 16 cards for functioning it's by far the easiest run i've had, despite the crappy start where you need to get rid of missiles and shields at the merchant.