Haunted Mines is a good Murky map though it is one of my least favorite maps to play.
I recommend the slime build with Octo-Grab as there is a lot of small skirmishes on this map.
The strategy here it is to push lanes and get camps. When the skeletons show up go down and get as many of the small camps as you can. Once you hit 40 skeletons head back to pushing.
When the boss starts up push the lane opposite your terror. Murky doesn't have enough dps to make it worthwhile to attack the boss