I just had to stop playing this game because I was basically making no progress every day. It became less enjoyable and more of a chore every 10 hours.

* Progress can be gauged by how far a team of heroes you construct can proceed in the "single player" stages of the game. Getting further into the single player campaign dictates how much experience/gold you will earn when not playing the game.

* In order to make progress, you need to upgrade a full team of six heroes.

* Not all heroes are equal and are graded on a scale of stars from 1 to 10, with 1 being the absolute worst and 10 being the best.

* The best heroes start at a star rating of 5 (I will call them 5* to mean "5-star" and so on). In order to upgrade a hero to 6* and beyond, you need a second copy of that hero and 3 additional 5* heroes of the same faction color to promote it to 6.

The drop-rate of getting 5* hero copies is very low across most opportunities. You can "summon" heroes from scrolls purchased with real-world-money, but the odds are very low here. There are also "prophet orbs", but these orbs are very rare and hard to attain more than one of them per day.

* There are many 5* units in the game, and gameplay-balance wise, not all of them are even remotely good in the later parts of the game. There's two tier-lists mainted: one for player-vs-player, the other for player-vs-monster. If you get a 5* hero unlock and it's not on that list, it's junk and is only used as food for building your 6+ characters.

There are ways to speed up the progress with money, but you will pay an arm and a leg to make about 1/6th of a dent in fully leveling a character. You'll be lucky if $100 USD gets you an inch.

It's very much a lootbox casino game hidden behind an RPG-style idle game. I played it for about a month and I was unable to hit level 90 in time to get a second copy of one of the highest-rated characters in the game (Heart Watcher), so it felt very frustrating and not very enjoyable afterwards.