My HDMI sound output acting weird?

[Windows Central Question]

Here's my problem:
My laptop using Windows 10, few days ago I connect it to my TV using a HDMI cable. There's no problem, the system sound, the video sound, all are working good.
But when I start a game (Hyperdimension Neptunia Rebirth 1), there's no sound. I opened up the playback devices setting and figured it out:
-My system sound & all other sound are using a Sony TV HDMI as a playback device (it automatically set to default playback devices)
-The game's sound using a Speaker (laptop speaker, game sound still coming out from laptop, its name is Realtek...)
Additional information is the game's intro sound is still coming out of TV. (maybe that intro is just a video file)
So the game must be using the laptop speaker as an output device, I can't find the option to change it anywhere (both windows & game option).
Imo I think that the game's problem itself. But I can't find out how to fix it.
I hope you guys have encountered the similar problem and have a method to resolve this.
Thank! (Sorry for my bad English but I think you guys can understand it properly)