Okay so its a good effort, I really don't like the pixel art of a bottle, maybe add a organic bottle ontop. Also the use of lava and water bottles in the middle, there isn't really a purpose for them, add iron blocks on the normal islands for a gameplay feature, as you can make buckets and now they have a purpose and people have iron blocks and can make iron armour. One change and its completely different gameplay. And change the normal glass to stained glass, just looks smoother. The middle should be a giant cauldron, and maybe an organic witch pouring in potions, then we can make it a halloween map if you add all these changes. So yah good luck :P