Head Ball 2 requires perfect timing of your character movement. That is why it is important that your internet is stable. For a smooth experience, it's important that you are connected to a reliable network, and that your device's signal is strong.
Full WiFi bars or mobile (cellular) data coverage alone is not always enough to guarantee a solid connection, as local networks can slow down, getting overburdened at times. This is especially true if you play in a moving vehicle or on underground public transport. As with any other online service, we recommend playing over WiFi with a dependable Internet service provider, or at least a solid 3G/4G connection with a reliable carrier.