The Update Alpha 0.16.0: Boss Update Title update for Minecraft (Windows) has 9 achievements worth 250 gamerscore.
Stay underwater for 2 minutes
Eat an Enchanted Apple
Cook and Eat Rabbit Meat
Spawn the Wither
Defeat an Elder Guardian
Dry a sponge in a furnace
Create and fully power a Beacon
Power a Furnace with Lava
Kill the Wither