Very generous with their Free-to-Play acquisition of "Premium Currency". All lower tier characters are upgradable to the highest tiers.
Some strategical placing of their summoning banner making it feel like they're trying to get you to spend money.
Been a fan of Fire Emblem Heroes and really enjoy the game. I've spent money on the game but to be fair I think I would have been fine if I hadn't.Re:Prodactyl has used this product for one year.