The steam exclusive items are pretty powerful. The orobas warhammer is +40 magical damage.
I've yet to find an excessively overpowered weapon in the early game, though. Overpowered for the beginning of the game though, yeah. But nothing I see that could last me forever. Besides the steam exclusive armor. Maybe.
Unless they changed the formula, do not underestimate the power of +damage bonuses on weapons. In Ego Draconis they got counted twice when combined with dual wielding and were more important than the base damage if you choose that weapon style.