50 years is a casual strategy with simple rules which requires high planning skills to beat it on Very Hard difficulty.

The gameplay is simple. You goal is to survive 50 years. Each year you get gold/wood/faith income which can be spent on hiring units and construction of buildings. Then you need to end the year. Before starting new year there is a big chance you will be attacked by enemies. If you survive it the next year starts. So the game is about good planning, you need to rise your army enough to stand against enemies, but if you will forgot about economy you will be outnumbered at the later stages.

Before starting the game on Very Hard i would advise you to play at easier difficulties to fully understand gameplay, see all units in the battle and try different faith skills.

Actually, this game could be passed in less than our. But you will start over and over again before you will find a strategy which brings you to the victory!

There are 11 nations in the game. Each has unique perks. I tried the most of them and in my opinion the best three are Greeks, French and Russian. Each has unique style of passing the game. Anyway, my opinion is not steel, probably you will find other nations stronger. Anyway, I am sure the game is passable with any nations.

The economy part of the game is pretty linear. You can hire peasant. Each one gives 100 gold per year. For hiring any units you need food which can be granted by building Chicken farms. There is also a forester's hut which gives gold income and food. And there are buildings which gives wood and faith income. So, you need to hire as much peasants as possible during the early game and than choose your defense plan to concentrate on 1 resource.

There are 3 basic defenders: militiaman, swordsman and knight. They requires gold.
There are also other 3 different groups of units. First part is paladins, exorcists and angels. First two requires faith for hiring ( they also need a knight). Angel costs gold and improve paladins. To make a good army with them requires a lot of faith.

Mythical units for gold, Minotaur and Hydra. Strong units with a lot of health and damage. Hydra also has useful ability. One barracks of them gives only 1 slot. So you need A LOT of gold to play with them.

Units which requires wood, Archers and druids are ranged units and unicorns are strong melee units. To buy them you need wood which can be produced by building lumber mills. But if you build them you will lose gold income. So, be wise with them

So basically in the game are 3 styles of playing, 1) with wood and basic units, 2) with faith and basic units 3) with mythical units

Let's try them all to find the best for you.

There are also skill system. By killing enemies or buildings special buildings you get faith. If you save enough faith you will get skill levels. There are 25 skills divide by 5 groups. I won't describe them all, you can read it on your own. In my opinion the 3th group is the best.

Finally, there are dungeons. You need some years to unlock and then you can try to beat them. Each dungeon gives reward. Some of them are really useful, so you should destroy them all before 50 year.

I made a lot of attempts before I passed the game. I won with Greeks. They start with Minotaur barrack and can hire them for free (but you need 10 food instead 1). Hydras are improved a little.

1) Beginning. You start with 1 peasant and 1k gold. Buy 2 extra peasants and call them all to the first battle. One peasant will die.
The next fight will be after 8 year. To during 2-8 years you need to build 3-4 forester's huts and 1 chicken farm and hire Minotaur. One Minotaur can eliminate next 4-5 waves and first dungeon.

2) During 8-20 years your goal is improve your economy by hiring peasants to build the next Minotaur barrack.
Minotaurs are basic unit of Greek, because if they die they can be bought with no cost. So actually, you lose nothing in the battle playing Greeks. Extra gold can be spent of economy.

When new Faith Skill appear, go for 3th part with forest skills. When the second skill come build 1 lumber mill. With this skill it gives enough wood for building archers and druids. Start making them and try to build 3th Minotaur barrack.

3) Hard wave with 2 unicorns and 2 druids after 25 year. This is game breaking wave. I don't remember exactly my army at this time. But i think i had 3 Minotaurs and 3 archers. I also bought some cheap knights.

After 25 wave there are 3-5 easy waves until the huge wave with 12 rows of enemies came. I used scroll of transmutation (which were granted by devil). I think, i could handle it without it but I was scared to lose.

Reach peasants limit to 30.
Buy hydra after 2th or 3th minotaurs. It's a strong unit but if it dies it splits to lesser hydras. If they will be alive after the battle each will become a base hydra. So if you are lucky 1 hydra could become 3 hydra. I was lucky :D

There will be a skill which will summon tiger after the unit dies. You need to have Unicorn barrack, so it will stay with after the battle. I have also destroyed a dungeon which gave me +1 tiger left as a reward. So I usually had 2 tigers in the army.

The 5th skill gives you a Treant, a powerful unit with 1000 hp and good damage. it's really useful, because it takes a lot of damage to yourself while your units kill other units. When it comes the game becomes easy walk.

After completing 3th Skill tree you have a choice. 1th skill is useless. 5th would be good, especially 5th skill but you won't have enough faith to reach it. So I chose 2th group. If you reach 4th it will give a scroll of shrinking which actually give you an ability to win any 1 fight.

4) Years 30-45. Use Minotaurs and the Treant as a shield. Hire new Minotaurs after their death. Archers and druids do a lot of range damage. Always have 1 hydra, if you will be lucky it become 3 hydras. If tigers and unicorn die it's ok.

5) 45-51 waves. You need yo destroy all dungeons. I got a scroll of shrinking and a demon chicken which were really helpful. Closer to the end hire 3 paladins and 1 angel.

There is a screenshot with my army at the final battle. I won it easily.
So, when you will win the game you will got really good fellings

Hope, this guide will help you.
Have a good game

P.s I also think combination of faith units with 2th skill group is really strong.