Not so much a bug as a small problem that might be able to be solved.
when you build the defenses close to the slime spawn point on the left side cliff, all the turrets start off facing the wrong direction. when they finally turn around the barrage of slimes have already torn down barricades placed close to it (can see the spawner on screen close, but not directly next to it. 3 spaces away) upon actually defending that spot the turrets stay facing the correct direction, allowing subsequent waves to be much easier. Until you try to swap characters or load a save.
Is it at all possible to make it so turrets will face the nearest slime spawner when built? or at least have them face the left side when on the left side cliff?
other than that. i do rather enjoy the game. the miner in particular is my favorite of the three.