Hello everyone, this is my first post here. If I’ve posted in the wrong category, please let me know.
This is a bullet hell engine I made for RPG Maker MZ. MZ’s battle system is diverse, but almost no one has implemented real-time bullet patterns, so I wrote one myself: it connects via a single file, has no mandatory dependencies, and allows you to create bullet boss battles, ARPG ranged combat, and bullet-dodging scenes using standard events.
Features
- 8 trajectory types: Spiral / Sine / Tracking / Boomerang / Orbit / Acceleration / Deceleration / Jitter.
A movement script interface is also provided if you want to write custom trajectories. - Bullets can actually hit events: Dual detection using tile matching + collision box overlap, with an optional SAT (Separating Axis Theorem) collision check. This specifically fixes the issue where bullets “miss when hitting face-to-face” that occurs with tile-only detection.
- Hit rates are configured via event page comments:
HitRate[n]/HitCondition[script]/MissEventPageId[n]/AlwaysHitBulletName:x(English syntax equivalents are also supported). - Target filtering: Filter by event name, by comment, or by “nearest hittable target.” Tracking bullets won’t chase decorative objects that can’t be hit.
- Throwable grenades: Parabolic trajectory + two-stage detonation + mirror bounce based on the component of the hit surface (walls only block horizontal paths, so throwing high enough allows you to clear low walls) + arc height can be set via tiles.
- RPG-style explosions: Area-of-effect damage, common events, and animations.
- Built-in 5 presets (Straight / Boomerang / Tracking / Throwable / Enemy Bullets) + 5 graphical plugin commands (Fire / Fire at specific position / Clear / Toggle collision box display / List presets).
How to try it
The plugin page has a free Lite version. It is not a stripped-down version: the engine is identical, all 8 trajectory types are unlocked, and there is no time limit. It only limits simultaneous bullets to 40, presets to 3, and offset groups to 2 lines. The Pro version removes these caps and includes a commercial license.
Getting started is a three-step process: Drop the plugin into js/plugins/ → Enable it in the Plugin Manager → Place bullet images in img/b_barrages/. The download package also includes ready-to-run example projects in both Chinese and English. Open them to see how presets are connected to events.
Regarding AI: The core of the engine (collision detection, hit rate binding, ricochets, grenades, explosions, preset system) was written entirely by hand. AI was only used for one round of performance optimization and for drafting and translating the English documentation. No AI-generated images or audio were used, and no content is generated at runtime.
If you are working on an action combat system, please let me know how it performs in a real project—especially regarding target filtering and hit rate comments. That’s the feedback I’m most eager to hear.
Plugin page (including the free Lite version): https://zhang03.itch.io/jiankes-bullet-pattern-system