also I would like to ask if the dust effect is a particle effect or hand drawn animated sprite? It looks really cool.
One more thing, does the boss have a idle state that he doesnt attack for a short time.
The dust effects on explosions/slashes etc are particle effects (just circles that have a changing radius and velocity). Glad you liked the effects!
For the boss: After each attack pattern bosses have a "post attack" time where they wait for roughly 1-1.5 seconds before doing the next attack, but they don't have any explicit "idle" phase (the wait time is baked into the end of each attack).