Difficulty curves that respect the player

I don't mind hard games. What I mind is games that are hard for dishonest reasons, like hiding information or spiking the difficulty to sell you a shortcut.

A good difficulty curve introduces one new idea at a time, lets you master it, then combines ideas later. Ironwall Legions does this well; by the time waves get brutal you already have the tools to handle them.

Readability is half the battle. If I lose and can't tell why, the game has failed me. Clear numbers, visible enemy types and honest previews turn a frustrating defeat into a lesson.

The best feeling in strategy gaming is beating a level you failed ten times and knowing exactly what you did differently. That only happens when the game plays fair.