A za těch 20 hodin mohu hrát jakoukoliv hru z jejich výběru?

Ta sluzba jeste neni ani ohlasena.

Samozrejmne zakladni myslenka je takova, ze hry budou k dispozici
v budoucnu pouze ve forme hodinoveho predplatneho.

Nebude mozne je upiratit, nebude mozne je cracknout.

Takže to může nějaký ten rok trvat než to Nvidia spustí?

Vse je popsano na webu Nvidie.

HOW LONG CAN I PLAY A GAME ON GEFORCE NOW?
You can play one session up to four hours at a time. After fours hours, you can save your progress and start a new session. This is to ensure equal access to our servers for all users during the free beta.

WHEN IS GEFORCE NOW LAUNCHING?
GeForce NOW is currently in beta for Mac, PC and SHIELD. Commercial availability will be announced at a later date.

HOW MUCH DOES GEFORCE NOW COST?
GeForce NOW is free during the beta.