Leveling up is tough

I played because there was a title quest, and I'm doing the hidden quests too since I get 100 gems every time I watch an ad. I combine items to create new ones, but my action points get used up and I can't move, so I need to watch a free ad to recover some when that happens. As others have mentioned, the screen doesn't turn off, so it seems okay to just leave it running. There might be a penalty for leaving it too long, but it's fine to start it during bath or meal times and check your phone when you're done.