I've always been fond of arcade shooters being EspGaluda my current favourite. Despite grasping gameplay thoroughly i never managed bullet hell patterns effectively. Enemy ships fire different shapes of bullets being arrow-shaped, rice-shaped or those blobbed ones that i can't figure out why sometimes they kill me and sometimes they don't. Is there some logical explanation for this behaviour or it's purely random?
All bullets harm you somehow, you just have to keep in mind that the hitboxes are much smaller than the actual player ship and the actual bullets, so sometimes they might appear to pass through you.
Your hitbox is shown during the how to play tutorial in EspGal.
Also if you're in the slow (pink bullets) mode then collisions will cause you to automatically bomb if you have any shield energy left, rather than killing you outright.