Endless Battle: Return of Hero +1

Simple idle game that actually has several interesting layers. There are a lot of resources that you can gain and resources from one place are usually required in some other place.

1. You have a hero killing enemies on the field. With each enemy killed he gains souls that boost your resource gains on reset of the facilities.
2. You can reset Hero progress or Facility progress separate from each other. When you reset Hero progress you activate quests that you selected, when you reset Facility progress you get unique resources that increase production rate of facilities on the next run and are used in the next set of facilities.
3. Facilities provide mostly resources required for other facilities but also provide Exp for a hero and hero class.
4. There are upgrades for facilities most of which increase production but some also provide bonuses to the Hero.
5. There are Spells that provide minor passive boosts to different aspects of the game, they also provide unique resource.
6. Several unique resources (gained from resets, from active spells, from killed bosses, etc) can be used to activate permanent upgrades. Activating those upgrades gives another unique resource that can be used to upgrade Spells.
7. There is a gatcha equipment/character system that lets you roll a random card which you can slot into equipment slots which are unlocked and upgraded by using resource that you gain when resetting your hero. If you recycle the card you get unique resource that also can be used in a feature described in step 6.
8. After you buy certain amount of facilities whole new layer (set of facilities, resource, upgrades, quests, cards, permanent bonuses) unlocks. As far as I can tell there are 9 such layers in total.
9. There are 3121 milestones with different requirements (level up a hero to a certain level, clear certain amount of zones in a region, build certain amount of buildings, etc) and several tiers in each that give permanent boosts when you reach them.

There are plenty of resource loops in this game where one feature provides resources for another. And there are some decisions to make, for example, if you want to make two short runs that let you get more resources at the end and complete two sets of quests or if you prefer to make a single long run that gives resources only once, lets you complete only a single set of quests but provides some extra bonuses during the run.

Overall the game is interesting and I recommend trying it.

Edit: after finishing it I want to add that the game is not very long (can be completed in about 18 days) which feels very satisfying when you can actually complete an idle game in a reasonable amount of time.

A decent game at first but quickly grows stale and tedious. Each "layer" is basically a carbon copy of the first one with different graphics and names. It could use automation for the buildings, prestige, quests, and missions, but then there wouldn't be any "game" left since there aren't any interesting decisions to make.

Idle games in general are often free, with optional things to purchase to support the developer if you enjoy it.
Putting a pricetag on an idle game means it comes under a lot more scrutiny than it otherwise would, because if an idle game is bad, at least you didn't lose out on anything.
Unfortunately, in this case that's exactly what happens, this game doesn't hold up particularly well under close inspection, progress feels slow, active gameplay seems pointless. And the game doesn't feel particularly enjoyable to play to start off with, making you feel like the money you invested was wasted.