GAME = Ganqi bay Amplifier Module for Earphones.
Stock amp = Standard amp.
Note that - unfortuneately - the GAME amp has an output impedance of 32 Ohm and that the Standard/Stock amp has a 18 Ohm output impedance. This is relevant for low impedance multi-BA IEMs since these usually will get a boost in the upper frequencies and a bass roll off. This might not be a bad thing with some (bass heavy, dark sounding) IEMs, but on others (bass shy, bright sounding) it will certainly pull the wrong way.
In addition the bass control will be lowered on dynamic drivers (compared to an amp with a very low output impedance). Not sure if BA bass-drivers will be affected in this way.