However, you will need to grind for materials that are not guaranteed to dnop everytime. There are skip tickets but i've never gotten one free. There is no continuous battle button so you'll have to click retry every 2 mins.
UI sometimes scales to my SS Tab S4, but most of the time it does not. Will cut off half the equipment screen.
So far there does not seem to be ways to earn paid currency. You'll have to do 34 stages or 340 ads for a 10 pull. You will also get gems for moving up in arena . A paid 10 pull would cost around $20-30, guaranteed a 2 star drop. 3 stars is max, currently 5 available for total of 0.99% chance for a 3 star.