Momentum Initiative: because combat can be strategic *and* fast!

The Initiative discourse is doing the rounds on Twitter again, but rather than chime in with a thread, I opted for something a little more permanent. Still, this will be a quick one!

Let's get the obvious out of the way: individual initiative feels like what @SprintingOwl aptly named dice clog. Side-based initiative, meanwhile, tends to sacrifice some tactical depth for speed. Popcorn initiative, while cool, can be easily abused. All of this has been discussed to death, but what about solutions?

Personally, I'm fond of what I've taken to calling Momentum Initiative. It's pretty simple:

• At the start of each round, roll a d6 to determine which side gets to act first (1-3, it's the PCs, 4-6, it's the enemies).
• If the player characters got the first round, they get to pick which PC will act first. If not, the Referee picks an enemy to act first.
• Whoever got to act first will then pick who goes next, regardless of side — a PC could pass the torch to another PC or to an enemy, and vice-versa.

"Wait a sec, V.V.", you might be thinking, "that's just a mix of popcorn and side-based initiative!". And hell, you'd be right... that is, if it wasn't for The Twist™ below!

• All enemies start the combat with a number of Momentum charges equal to their HD.
• Momentum charges can be spent to 1. act immediately, 2. inflict Disadvantage to an attack roll, 3. activate powerful abilities*, or 4. take an extra action at the end of the round.
• Enemies regain charges when 1. they get a critical, 2. they kill a character, 3. they succeed in a morale check, and 4. when they are attacked by multiple PCs in succession. Only a single charge can be recovered each round, no matter how many times this is triggered. Enemies can never have a higher number of charges than their HD.

The addition of Momentum is meant to prevent the players from abusing popcorn initiative and turning it into just another version of side-based initiative. In my experience, this actually gives them an incentive to avoid ganging up on a single enemy, lest they fill them with Momentum charges. 

Now, one might argue that these Momentum charges are yet another thing for the Referee to track, and while that is indeed true, the tactical depth they add to combat can be worth the extra bookkeeping. Besides, if you're already tracking HP, this shouldn't be such an increase in cognitive load, anyway.

* I'm very fond of making a d6 list of possible actions an enemy might take in combat, which usually includes lower odds for activating specific abilities than for attacking or doing some weird, enemy-specific shit. Momentum allows enemies to spend charges to trigger these abilities whenever they want, though, bypassing the bad odds. If you're not using anything even remotely similar to this, please ignore that option!