Game music/assets/video/footage are no different to other music as stated by other users.

Some companies have a clear policy when it comes to streaming or making videos with their assets such as Blizzard (https://www.blizzard.com/en-us/legal/dd76b654-f2c4-4aaa-ba49-ca3122de2376/blizzard-video-policy) while others don't and can take legal action at a moment's notice if they so wish to.

It falls upon the streamer to check if they can legally stream said game/music or not.

Some years ago, Nintendo did try to enforce people join their Creators Program to make videos (https://en-americas-support.nintendo.com/app/answers/detail/a_id/14034/~/nintendo-creators-program---overview), where the creator got a percentage of the Ad rev. They eventually took a step back as people simply stopped promoting their games. Current Nintendo guidelines: https://www.nintendo.co.jp/networkservice_guideline/en/index.html?n

Try looking up "<game> streaming policy" and if you don't find it, it's a risk you're taking.

What about Rhythm games where music is the main part of the game?

The problem is that copyright law in the U.S. is extremely outdated so it doesn't really account for technologies like computer games and console games moreless interactive streaming platforms like Twitch.

All content in such games, including cut-scenes, background music, sound effects, textures, models, and other assets is intellectual property of either the original game developer or their game publisher. That means if you broadcast any such content online without authorization, then you are infringing on the exclusive right of public performance (music, sound recordings) and/or public display (visual works).

Most game developers and game publishers haven't pursued legal action, thankfully. But it is well within their intellectual property rights to do so at any time they choose. Moreover, even if rightsholders haven't yet pursued legal action, that doesn't mean it is legal to broadcast games online anyway. Rather it is a gray area that has yet to be tested in a court of law.

This is why we need to extend the U.S. Copyright Act to account not only for digital artistic works and but also the vastly changing legal landscape for the use of all such works, so that both creators and consumers can benefit.

It's not different.

I don't like how in-game music doesn't count as a reason for not having a copyright claim. I've been trying to do Star Wars Battlefront 2 and Halo and because of the in-game music I got copyright claims on the stream and had to delete them all.Twitch team, please fix this problem