Even as a fan of idle games, I've got to admit that these games can be boring when they're not unique. And Idle Guardians...is not remotely unique.
This game has all the stuff you'd expect from a fantasy idle game: recruit pixel-art heroes, fight pixel-art enemies, purchase pixel-art upgrades, and then reset and start over from the beginning with slightly more powerful. Rinse, repeat, forever.
If you love this formula, Idle Guardians is fine. But it just doesn't do anything to set it apart from the pack of dozens and dozens of other idle games, many of which do it better or have something more original to show off. This one didn't keep me interested longer than one night, which is barely scratching the surface of most great idle games.