aEntryType is not a tString, it is an eSoundEntryType
https://wiki.frictionalgames.com/hpl3/ga...nd_playgui
Possible values for eSoundEntryType (in hps_api.hps)
enum eSoundEntryType
{
    eSoundEntryType_World,
    eSoundEntryType_WorldClean,
    eSoundEntryType_Gui,
    eSoundEntryType_GuiWorld,
    eSoundEntryType_Safe,
    eSoundEntryType_WorldAll,
    eSoundEntryType_GuiAll,
    eSoundEntryType_AllExceptGui,
    eSoundEntryType_All
};
These pretty much mean different "mixing tracks", as in if you play a sound in Gui and fade the World sounds, the sound you were playing in Gui will not be affected.