Just saw this thread in my digest.
Note: I am not a lawyer.
Keep in mind, by using the word Twitch in your apps title, you could be violating the Brand Asset Guidelines, specifically:
Do not use Twitch in the name of your applications, products, domains, etc. This includes merely adding simple letter or number combinations (before or after), e.g. “Twitch1234”.
In doing so, you could lose access to the API (or could possibly have your app removed from the Google Play Store) as defined in the API Terms of Service
You agree to comply with Twitch’s Brand Asset Guidelines , incorporated herein by this reference.
I’m not sure how strict Twitch is in regards to this, but considering the word “Twitch” is trademarked, I believe they are legally required to defend their trademark.
@Fugiman or @george might have some more info regarding this.