A core sits in the center, spinning, and your only job is throwing pins at it one at a time until every pin is attached without a single collision. Clip a pin that's already stuck and the level resets instantly, no warning, no partial credit for how far you got.
Early levels move slow enough to learn the basic rhythm, but the rotation speed and direction shift constantly as you climb through the level list, and later stages pack pins in tight enough that there's barely a gap to aim for. Watching a full rotation before throwing anything sounds like it should slow you down, but it's usually the difference between clearing a stage and restarting it for the fifth time.
Controls: Click or tap to launch a pin toward the core.
It's the kind of game people open for "just one quick round" and somehow still be playing twenty minutes later. Play Coreball unblocked at google classroom 6x and see how many pins you can land before one clips.