The only available game mode right now is "Endless", so the game goes on as long as you want. Most people will struggle to get past 2-3 hours until they get more boons and upgrades unlocked. One Korean player told me he has a game save with over 1,400 hours on it.
If you want it on mobile, contact us for a free promo code with your preference for iOS or Android (the codes expire in a week or two, so get one while you can).