If you are familiar with Black Powder you will find Hail Caesar very easy to pick up, and if you like Black Powder, you will undoubtedly like Hail Caesar. Rick Priestly wrote both. Hail Caesar runs on the same principles as Black Powder, but has been tweaked in significant ways to provide a good ancient feel.
The book is a joy, written in a clear & amusing style and superbly illustrated with modelling porn. The rules are laid out in a logical sequence and although there is no index, a good contents page makes things easy to find - plus stuff is generally where you expect to find it. There is also a concise summary and easy to read quick reference sheets in appendices.
The rules are very tolerant of basing systems and figure scales. They are unit based, so all that matters is that both sides have units of similar width. The book is illustrated with grand battles with large units of 28mm figures on huge tables, but the rules facilitate the use of smaller units if necessary. We have been using 15mm figs on an 8x5 table and it works just fine. You could even scale the unit widths, moves & ranges down and use a 6x4 table if you had you.
Different troops types are provided for with a range of generic types plus special rules for special cases. Units sizes are restricted to standard (160-200mm frontage), small (half) & large (double). Units are grouped in "divisions" of 2-6 units for command purposes. I can understand that some will find this lacking in subtlety, but out on the table in the midst of a big action, the simplicity pays off.
The command system Hail Caesar shares with Black Powder is a particularly distinctive feature. It adds a level of uncertainty and excitement that for me is much of the appeal of Hail Caesar. The procedure is that before moving a unit, or group of units in the same division, the player must announce what he intends, then throw a sum-of-two-dice command test. The unit may then be allowed to move 1, 2 or even 3 moves within the limits described, or not move at all. You have to be very careful how you word your order, or units can get into trouble real quick. Movement isn't entirely dependent on the command test: Units close to the enemy can act on initiative and some units, like those given the "drilled" rule, can move 1 move even if they fail the test. Movement rates are less than Black Powder which helps maintain cohesion in the ancient armies.
The combat system is a little more complex than Black Powder, as it should be, as hand to hand combat is what ancient warfare was all about. But it's still simple enough. Units have a "clash" & a "sustained" combat value, the first used in the first round of close combat and the second subsequently. This is the base number of dice to hit. Extra dice may be allowed due to support. The to hit score is 4+ with some tactical +/-'s. The target gets a save for each hits. The save depends on armour, morale & some tactical factors. The side with the most unsaved hits loses and takes a sum-of-2-dice morale test that could cause disorder, retreat or rout. The system isn't original, but so what - it's as easy and quick to resolve as any. We have found the results to be a bit capricious sometimes, but we are also not entirely across the tactical options yet, and what rules can save you from a cluster of 1's ? At least with this system you don't get a headache as well.
Missile fire hits are adjudicated in a similar way to close combat with units given so many dice to hit depending on size, skill and weapons & the target having a save depending on armour, morale & cover. Too many hits will cause a morale test that could cause disorder, retreat, or with enough casualties, rout.
Casualties are recorded with chits, a small dice, or wounded figures. When hits reach the unit's stamina value, usually 6, the unit is "shaken" & becomes more vulnerable to morale tests. At the end of each turn excess casualties are removed - the effect of further casualties is in causing more morale tests - the piles of chits don't get out of hand, being replaced by a shaken counter. The stamina values are higher than in Black Powder thus causing combats to last longer, as they should for ancients.
The default army morale test is that an army is defeated when more than half its divisions are broken. (Divisions are broken if more than half are routed, or all are shaken). Specific scenarios can have different conditions.
The game mechanisms are simple and easy to follow. You can fight big battles with these rules and complete them before your brain fades or the sparrow farts. Most of the concepts are well explained & easy to grasp, but there are a few loose ends that might take a bit of thought. There is a list of optional rules for players to pick & choose from to suit their prejudices. Hail Caesar is not intended for serious tournament play, the intention is for a good game between like minded mates. The author encourages players to experiment & go the way they want - the rules are not meant to be taken as writ in stone, nor proof against rules lawyers. I can see that different groups would evolve different ways of doing some things - when playing away one will need to accept the home group's way of doing things, but once familiar with the system, that won't be difficult.
The book provides seven ready made scenarios with terrain, army lists and a description of the game as played. They are spread over the time from Biblical times to the Middle ages. The scenarios are an interesting mix, with encounter battles & holding actions as well the usual line-them-up-and-charge. All the scenarios could be re-jigged to different periods to suit the armies available to provide even more variety. Players are encouraged to evolve their own scenarios, preferably with a capricious umpire to make things interesting with secret rules.
There isn't a comprehensive points system provided. The emphasis is on the players devising scenarios, preferably multi-player with an umpire, rather than picking armies from a Chinese menu for a competitive one on one game. There are just two army lists with points provided - for Romans & Celts. Other example armies are provided in the scenarios. More lists are already available on the web (Warlords or Yahoo Group forums) and there are plans for future books going into specific periods in more detail and including lists, so list addicts will be catered for.
The differences with Field of Glory are stark - they are chalk and cheese. I personally found FOG to be overcomplicated and dull, but I'm sure there are people who will not like Hail Caesar's free and easy approach. I think the two sets of rules will appeal to different sets of wargamers & few will like both.
We have been playing Hail Caesar with my grotty old 15mm figures, but it would be nice to see the spectacle of mass 28's like in the book. I know several people have a few units of 28mm, but only Carl has enough for a full army. Hail Caesar would be perfect for a multi-player game with 2 or 3 players a side, each with a division or two of their own troops.