The game's main challenge

The central thought behind the Heroes of Arcana design is resource management. All the other elements are secondary.

When its development started about ten years ago, it had no purpose other than being a fun tower defense. Soon, I realized that this was not sufficient to keep even myself engaged in the development, so the project stopped and restarted dozens of times since then. 

After a couple of years came the desire to develop a game incorporating business and resource management knowledge. At this point, I realized that those concepts are essential to tower defenses and other common game styles like roguelite and deck-building. So, this idea was incorporated, and HoA changed from a simple TD to a resource management adventure.

The game's main goal is to survive for 8 stages while collecting as much Arcana as possible at the end. On the one hand, summoning heroes, casting spells, and improving the deck might increase the player's chances of finishing the game, but on the other hand, it decreases your final score. Therefore, to achieve a high score, the player needs to take risks and use only the resources necessary.

But that creates a big design problem: saving pennies at a game is not a fun idea. That's when the big quests are incorporated into the game's concept. They are challenges that increase a stage's difficulty but give extra rewards to overcompensate for the resources the player spent to overcome them. This enables the more experienced players to apply powerful combos while getting outstanding rewards but with a higher risk.

Those concepts are still being incorporated step-by-step into the game, but I would love to know your thoughts.