This game will suck you in. But don't play on very hard/very hard if you are new.
It was nuts.
For the first 20 years or so (40 turns) I was fighting Greece on Sicily. They keep attacking and I keep defending. I commanded pretty well and the Greece suffered crushing defeat after crushing defeat. I even blocked both of their ports on that island to slow down their economy. Both of the cities on Sicily together would cost the Greeks around $6k each turn.
However they still grows. They still breed like rabbits. In that 20 year period they must have suffered over 6,000 men of losses (including once where I sunk a ship full of soldiers of theirs. Probably a 1,000 guys killed without a fight). However guess what happens a few turns later? They bring an army sized around 5,000 (in 2 armies) against me. Not on that, those 5,000 were their elite troops. So as I slaughtered them time and time again, they keep growing even bigger and the troops gets better trained.
All the while I thought I had a huge economy advantage because they were losing $6k from those 2 cities each turn. You see, I was only getting around $500-1k each turn from my two cities combined, so I thought $6k is a lot of money to loss, and that Greece will collapse soon due to debt. Boy oh boy was I wrong.
It was only later that I found out that the computer gets $10,000 for free every turn in very hard campaign mode. I would take me 200 years to get a TOTAL cash of $10,000 in my bank.
I was hard pressed to train troops and build up buildings. I build ports, roads and markets as fast as I can. However each time the Greeks attack me, all my trade stops and I made very little income, and they attack almost none stop.
Being attacked also stops my unit productions. I only had 2 cities, so when they attack my city on Sicily I lost 50% of the unit production. So 50% of my income, 50% of my unit production and 50% of my building construction each time they attack me. It was actually more than 50% because my capital city barely makes any money for the longest time, and so I had to rely on my city in Sicily for most of my income. I was also constantly under the attacks of crazy pirates with their huge fleet of 800 men (WTF???) They often push my fleet back, or I had to go around to avoid them. That really delayed my reinforcements to Sicily. A few times my reinforcements don't make it in time so Sicily need to defend itself with a army smaller than 1,000 men.
I would say the Greeks siege me every 6 or 7 turns. And each time they bring over a 1,000 men. I had to rely on Town Watch and Velites (Javelin guys) to just barely match their army size. However, as I said previous, eventually the Greeks brings out an army that was twice my size and was better trained than I am (5,000 elite troops vs 2,500 Town Watch+Velites, gg).
It was only later I find out that in very hard battles the computer units get +7 to their stats. So their attacks hurts much more and their armor were much higher. It was a miracle that I was able to held on for 40 turns.
I decided to not bother with this hopeless battle. I retreat all my soldiers back to Italy. I disbanded all the Town Watches to reduce maintenance costs. I focused on building up economy and technology.
Eventually I took Creta from the rebels, which for some reason everyone forgot about. And then later Rhodes in 129BC, also from the rebels, after they rebelled successfully against Greece (Ha!). So the areas I controlled came to an astonishing THREE .
Of course by then my 2 allies and taken over almost the whole area. Julii Had token a large part of Western Europe. Brutii Had taken like 80% of the area to the east. I will probably become a vessel state to whoever attacks me first.
It was fun, but I don't think this campaign is gonna go anywhere. I will probably have to restart, this time with normal/normal.
One thing I did learn about this game, Praetorian Cohort + Scorpions rocks. Pratetorian Cohort counters basically anything as long as you don't let enemy calvary charge their backs. They are basically immune to missiles with their formation. They slaughter pretty much all other foot soldiers. Against cavalry they will lost a few guys due to the initial charge but once the battle is engaged they would eventually overpower the cavalry.
Scorpions and onagers absolutely murders troops if you have enough of them. In one battle some middle east guy attacked Creta. He had like 1,200 men. I only had around 600 (240 Praetorian Cohort, 240 Scorpions and around 100 general's cavalry). It was a total slaughter. I killed 99% of his guys and only lost around 20 men. You just have to make sure you don't put your own units directly in front of your Scorpions, since their misfire WILL kill your units. Earlier in the game archers can fill this same role.
Also don't charge your calvary into your own troops. That will kill them too.
Town Watches benefits the most from blacksmith upgrades. They are also pretty deadly with a good general leading them. However until you get both they are not worth building. You are much better off using real soldiers. And never ever charge Town Watches into enemy formation head first. They loss to absolute everything. Even archers in melee will beat them (in very hard battles). Instead Town Watches should be used as back stabbing assassins. Have your real soldiers fight enemies head on, while Town Watches run to the back for free kills and cut off any exit. Obviously this is a very high risk maneuver. But the great thing about Town Watches is that they are complete expendable.
As for econ, don't bother with markets until the very end. Build ports, increases population, upgrade palace, repeat. Markets bring very limited economical benefit and very limit population growth, so it should be low priority.