you can try to download Pixel Gun 3D for pc and then transfer them to your devices. It is quite easy. I often do it for other apps. of course if you are using bluestack, it is fine.
Follow these steps:
1. Come to download APK file at reliable site
2. Download apk files, remember where you have saved this file.
3. Debug your device with Pc and transfer file.
4. Open your android devices, choose that file and do follow the guide (remember to allow to install any apps without coming from Google Play in the setting)
Finish and good luck
