[Dec 16 Updated]
There is a new warning said "Permission denied (1)" happened to some players with new Xiaomi devices like MI 9 and Redmi 7 even if MIUI optimization has been turned off. The solution is:
1. Make sure that MIUI optimization has been turned off;
2. Restart the phone;
3. Go to [android] - [data] - [com.qooapp.qoohelper] - [files] -[download], then find the apk and install it manually.
* List of phones which might have the problem above:
Mi 9T Pro
Redmi Note 7
Redmi Note 6 Pro
Redmi K20 Pro
Redmi note 8
[March 22 updated]
ATTENTION: Some Xiaomi devices need to be RESTARTED after the setting being changed, or you might run into force close when you redownload the game!!!
Tips for those who had "invalid apk" problem while you installing: You need to turn off *MIUI Optimization* in the phone settings (works on Mi phone).
7. REDOWNLOAD the MASS FOR THE DEAD and you can install it!!!
Open Developer Mode may cause some unexpected problems, but you can turn on MIUI optimization and turn off developer mode after installing the apk. It won't effect the game.
Hope it helps you guys! Android phone is kinda troublesome indeed, but we like it anyway coz there are some many japanese games we can play!!