Play Onmyou Taisenki Zeroshiki (j)(caravan) Online

Onmyou Taisenki Zeroshiki was a Japan only release for the Game Boy Advance, part of that era where developers were really pushing what the handheld could do with sprite based action games. I believe it was published by Caravan, though details in English are pretty scarce. It fits right in with other mid 2000s GBA titles that offered a specific, niche kind of experience.

You control a young onmyouji, a practitioner of Japanese esoteric arts, navigating side scrolling stages. Your main goal is to purify areas overrun by yokai, which involves a mix of platforming and combat. Your primary tool is a talisman you can throw at enemies, and you can also summon shikigami familiars to assist you in battle, each with different attack patterns. The game is structured screen by screen, requiring you to clear all enemies in a section before moving forward. The pacing is deliberate, and the difficulty can be sharp, especially when managing your spiritual energy for attacks and summons. It feels like a methodical test of your timing and resource management as you progress.