Hard on the game and kill monsters do not drop items.

I saw the need to report bugs!
1.
It's really hard to get the game, had to wait 2 or 3 minutes is very long.
2.
Kill blaze, not dropping items: blaze rod. Kill the skeleton wither, do not drop items: skull wither.
3.
When clicking on the settings, it will reach 5 -7 sec trimmer. And while the world prepares to create similar new trimmer.
4.
Sometimes when approaching zombie spawn yard, will fall 1-10 fps.
My device !
Name :Pantech Vega Secret Up A900L
CPU: 2.3GHz Qualcomm Snapdragon 800 4 x
GPU: Adreno 330
Android 4.4.2
I wish the game with the command: gamerule keepInventory true.
I look forward to the game the game will soon be an official update as soon as possible.