Badman 3D has a multiplayer mode

Acquire revealed what the third "D" in "3D" stands for in Yuusha no Kuse ni Namaikida 3D (Badman 3D) and it’s a two player mode called Family Dungeon.

Both players share a dungeon in Family Dungeon and the goal is still to defend your home from invading heroes. The dungeon is divided into two parts, pink and terracotta, for scoring purposes only.