Swipe across the orbs in the direction their arrow points to slice them, wrong direction just misses, no penalty. Slicing a bomb in ANY direction ends the run instantly.
Every orb in Neon Slice comes with an arrow telling you which way to slice it, get that wrong and you just miss, no harm done. Slice a bomb from any angle, though, and the run ends right there. Free, fast, and unforgiving about that one rule.