1. While using a virtual joystick no other buttons are working. E.g. moving character and pressing grab button on the right does not work.
2. Sometimes character keeps moving while virtual joystick is not active. I guess it needs something like a dead zone.
you can make an option to make a virtual joystick invisible and usable on any part of the screen like in other mobile games. I.e. if a player starts dragging in the direction on any screen position, the character starts moving and virtual joystick is active, when player realeases the finger virtual joystick is disabled. This will make the game more enjoyable on a mobile screen. Currently virtual joystick is suboptimal, I would rather play with point and tap which is kinda tedious, but still better than current implementation of the virtual joystick