I've made another boss map, pretty simple in layout, but I wanted to try out the new sky and water/lava choices on the MapMaker. I figured columns are pretty blocky anyways.. so it shouldn't look to ugly with the tiles clashing. I figured making a liquid border around the map was worth going for (it looks really awesome when the sky is dark and it's lava!)
It should be fine for any boss battle (an Amoeba will punch holes in the various platforms floating around.. be careful!).
Toss into AVWW\RuntimeData\Logic\RoomMaps\GeneralBossRoom to use. Enjoy!