I can tell whether I will like a tabletop game by looking at three things. First, how the injury system works and whether it uses a shared resource. Second, how the character sheet reads. Third, what it uses for an initiative system.
Initiative systems are very important in a tabletop game. They are largely responsible for defining how a player interacts with the game. They are largely responsible for the pacing of the game. They are also largely responsible for keeping the attention of the players.
I really dislike initiative systems that are predictable, repetitive, and non-interactive. I can work with them; I enjoy running Pathfinder games for example, but these initiative systems work against me rather than with me when trying to keep the players engaged in combat. I tend to look for an initiative system that accomplishes several things:
~ The players don't need to roll initiative for every action.
~ The order of the combat actions are hard for the players to predict.
~ The players can take some actions on other players' turns.
~ I can keep the pace going using a quick countdown method.
The first point is obvious. Having players roll for initiative for every action slows down the pacing of the game. It's unnecessary and take away from the game. The main problem with this system is that the order of player actions is still predictable, it just changes from round to round.
Having a system that requires a roll for every 3 actions, however, seems to be the sweet spot. The new initiative throws a bit of chaos into the mix and the rolls aren't so plentiful that they become annoying. I find that an initiative roll every 3 or 4 actions generally means there are two initiative rounds per combat. Sometimes long combats require three rolls. The initiative rolls give a better sense of how many actions have passed in longer combats than round robin in an initiative order. The round also gives me a convenient set of actions with which to limit abilities. That seems to work best for my style of game.
The second point is a little harder to explain. One would think that being able to predict upcoming actions would be a benefit for a game, but I find just the opposite. If initiative moves in a set pattern, like in d20 where initiative is rolled once and then goes in that order for the length of combat, then the players tend to become complacent and inattentive when it isn't there turn. To wit, if a player looks up and says "Sorry it's my turn" then someone has done something wrong.
Instead the players should be listening to a fast initiative countdown to get their next action. Since they don't know the order of the current round until players speak up they have to pay attention. More importantly, there should never be a initiative mechanic that makes it seem like it will be forever until their next action. When that happens players start futzing with their laptops, start researching alternate builds, and generally lose interest in the combat until things come around to them.
Yes, a big part of this is the pace at which the gamemaster calls out and executes actions, and the pace at which the gamemaster expects players to do the same. But the initiative system itself can be very helpful for this, and it can also make this process more difficult.
The third point is very handy if you want to encourage players to pay attention, and probably the biggest omission of most systems I play. If you want the players to pay attention to combat, you have to give them some actions they can take in response to what is happening in combat. You can't have them take their one action and become inert as you work around the table and expect them to have a vested interest in all the other actions. If they can take minor actions to hamper enemies or aid friends, even when it's not their turn, then the initiative system is encouraging the rewarding them for staying engaged in the combat flow.
The fourth point simply means that the initiative totals should not be so high that it's awkward to count down the totals. I would rather start a quick count from 10 to 1 then counting down from 33 down. Yes, I can accelerate the countdown (and I do) by calling out the initiative countdown in larger increments. I ran many games of Villains and Vigilantes and early Shadowrun. I just prefer lower totals.
Let's assume I have more players than I intended and I am game mastering for 9 players. The players are reasonably well versed in the game system, but let's face it with 9 players a game master will probably be challenged keep them all engaged and moving combat quickly.
My favorite initiative system uses individual dice to create a random spread of actions. As an example let's look at 7th Sea. You get one ten sided die for each action your character has. Throw them all and set aside each individual die (or at least its value) to determine the phase during which you can act. The values range from 1 to 10, thus the game is designed with 10 phases.
The average NPC and the minions have two action dice, the combat capable characters have 3, and the fast or very capable characters get four. If a PC with three actions rolls a 9 and a 4 and a 2 then those are the action phases they will act on. If I start counting down "10..9..8.." that player would call out 9 and I'd direct them to briefly describe their action.
With this system when I start the countdown no player knows how many people are before them unless they are trying to observe all the initiative rolls of the PCs to see how they all did. That's fine, since those players watching all the initiative rolls in engaged in the game.
If someone rolls doubles in my system they get a special "double action" so even though doubling up reduces your actions you at least get to use special attacks during those actions. I like this system because it provide natural opportunities to use special heroic actions. I also like this system because the number of actions can also vary. As an example, it's possible for someone with 4 actions to double up twice and only get two actions. As the game master I only have to count down 10 numbers regardless of what the players roll.
The key to this initiative system, however, would be if the players have a few "interrupt actions" or perhaps "open actions" that they can take any time, even if someone else is trying to describe their own action. These open actions cannot be complicated since they would bog the game down. They just have to be interesting and beneficial enough to warrant paying attention.
As an example, let's say a player had two open actions per turn. Through various character options the player has the following open actions.
~ After another character declares an attack you may use one of your open actions to give them +2 to hit for that attack.
~ After another character declares an attack you may use one of your open actions to give their target +2 to defense for that attack.
~ If a character moves through your threatened space you may se an open action to take a single attack against them.
With these simple options the players will probably be paying attention to the combat even when they are not up for an action so they can make good tactical decisions about how to use their open actions. So long as I keep a brisk initiative count, and I will in fact keep the count going if a player is not ready to act when I call out their number, the combat moves along and players are rewarded for paying attention.