What's the difference between Overwhelm and Stun in Dragonfire?

Control is not one single thing: several types exist and they block different actions.

• Stun (the classic): the target can't use Orders, habits AND basic attacks on its turn. The most complete lock.
• Overwhelm: the target can't use its active Orders and habits (but not necessarily its basic attack).
• Attack-modifier stun: blocks the attack modifiers plus the basic attacks.

The control family covers stun, stagger, overwhelm and confusion. Some Orders scale with control: Rhysarion deals +30% fire instead of +20% when the target is under a control effect. Knowing which control you're applying changes what the enemy can still do.