Once you enter the gatcha zone you can choose from 5 different coloured stones, red for fire magic/sword, blue for lance/lightning magic, green for axe/wind magic and colourless for healer/probably
If you choose from the same selection you have a little discount like 5->4->4->4->3 gatcha stones per roll so in the end you only use 20 gatcha stones instead of 25 if you quit the selection every time(which you probably won’t do lmao)
The highest star count you can get is 5-star!
When you roll watch for a little puff of smoke before the rock goes blue, that’s the animation for 4 or 5-star, if there isn’t you got a 3-star
You get a special character animation if you do get a 5-star(edit: only pickup targets get a special animation!) so that would be obvious
After your four rolls you can just delete/clear data if you’re on android and retry
You can skip all of Anna’s dialogue and so on which is a+ too