I have beaten Antebios with each character class. Here are the most annoying things about the game.
1) Runik weapons are SWEET, but unobtainable. Only once did the Mustache of Cleaverness actually show up in my inventory. Then my computer broke and I lost it forever. I have no idea how that happened and I haven't been able to find another one. This item must be made easier to find. Or just tell us.
2) Runik weapons are SWEET, but unobtainable, so it is colossally annoying that the dungeon achievements don't work.
3) The Hero Badge stops working after...I'm going to say two purchases? It should be clear that the Hero Badge either no longer has an effect on store items, or that you need to keep buying them to actually get Legendary store items. This happened once, never again. Again, you need a Legendary weapon to get all the achievements and start again with Runik weapons.
4) Lower-level weapons outperform higher-level weapons. If a weapon is level 100 out of a possible 100 then my Level 91 Tree Branch shouldn't have a higher attack. Similarly, the excitement of Level 100 armor is completely gone when nothing beats Level 90 Crystal Armor. Why the hell am I even doing the last dungeon or bothering to reach level 100 if there's nothing there?
Runik weapons should be awarded at level 100 and/or when you kill Antebios. Having them tied to an achievement system that doesn't work is cruel.