[MangaD]

I see. I have heard about the black screen bug before and it was usually related to low memory. On iOS devices, it was usually the low storage memory. But your case is Android, so I can only think of RAM. This is the first time I hear about Lucas upside down though.

Here is what you can do. You can e-mail Marti: hfx@martialstudio.com

And explain to him everything you said here:

1. Downloaded it from Google play and installed it yesterday;
   
2. Smartphone is Samsung Galaxy Gt-S5301; Please confirm the below specs.
   • Android OS v4.0;
     
   • 850MHz Processor;
     
   • 512MB RAM;
     
   • Dimension (WxHxD): 57.9 x 104.9 x 11.98mm;
     
   • Resolution: 240 x 320 pixels.
     
3. When you play with it the screen goes black and when you press the attack button you see Lucas upside down slashing very high zoomed (sometimes); By the way, does this happen right after opening the game, or during gameplay?
   
4. Killed a lot of processes and have a lot of free RAM memory and reseted the phone before installing HFX. But the problem still persists. Would be nice if you could attach a picture with your free storage memory and your free RAM memory.
   

After this, Marti will try to assist you. There are some chances that your phone doesn't meet the requirements to play the game. I don't know what the requirements are unfortunately, it depends.

If you do manage to solve the problem, please let us know how you did it. ^^