I think this game isn't "free to play" but rather "free to try".
Let me explain:
To fight monsters, earn items, crowns you need to go into dungeons. Entering dungeons costs energy.
Energy costs 7000 crowns (at the moment of making this post, price doubled since the game went on Steam) or $$.
Sure, you get 100 mist energy, which can be used in elevators, every day. But how long will that mist energy last you? One dungeon ride.
Are you satisfied with 7 dungeons a day? I'm not. For me 1 dungeon ride is a "try" rather than "play". And to get another 100 energy I have to either spend _everything_ I made in that dungeon ride, or wait for a day.
This seems more like a subscription-based game to me with subscription costing $20 per month (for starter pack, which should last you a month) than a "free to play" game where you get "premium" features for $$.
What do you think, is this game a true "free to play" game or is this all just marketing?
Did you pay real money to download any content or play any part of the game? If not, then it clearly is a free to play.