Never let the combo meter drop to zero. Even if you aren't hitting an enemy, break a crate or use a movement ability to keep the chain alive.
Use something with a "Bleed" or "Damage over Time" (DoT) effect. The bosses in this stage have high physical defense but low elemental resistance.
Don't go for the optional gold chests unless you have more than 2 minutes on the clock.
Watch the bull icon/meter. Activating this too early results in a wasted cooldown, but waiting too long can lead to a "Stun" lock. 2. The Optimized Pathing Strategy