What is a wall good for? Many have asked this question, but not many know secrets of the wall. Under certain condition the wall is actually helping the attacker. For example a low-level wall would ensure that a whole row of defender's archers, slingers or sulfur carabineers, as well as his entire deployed artillery will be wiped out in the first round.
In case of a high-level wall it is possibly for the attacker to breach the wall in 1 or 2 sections only, retreat his mortars and replace them with rams or catapults. This will ensure a very unfavorable casualty rate for the defender. The defending infantry will rush to plug the gap in the wall and it will be outnumbered by the attacker's frontline, plus all of the attacker's second line will concentrate their fire into the breach.
The wall however is useful for the defender if he has just a few troops in the city. For example a single slinger behind a high-level wall will ensure the battle going for as many rounds as are needed for every section of the wall to be demolished. This of course would only happen if the attacker is not using bomber balloons.
As an example I will give this scenario - I attacked a city that had a level 20 wall, 1 slinger and 1 spear-man in defence with 30 catapults and 50 spear-men. On this particular server I am a small player with a penchant for looting big players. The result was a 5 round battle; I finally won, but it cost me 1h and 15 minutes and 17 speamen. Earlier in the day my other pillaging team run into his main army and I lost all spear-men and 6 catapults. But they are cheap to replace - much cheaper in fact then 188 ship-loads of loot I took from him. Had I used 30 mortars I would have won in 2 rounds, same as if he had just a level 1 wall. In fact you need a wall level 25-26 to even hope for a 3rd round if the opponent is using mortars. But as has been demonstrating a high-level wall may keep small players that have only rams and catapults away from your warehouses.
A useful troop combination - what in Evony we used to call rainbow - is to have one of each troops in the city. You should have 1 spear-man, 1 hoplite, 1 swordsman, 1 slinger, 1 sulfur carabineer and 1 steam giant - a total of 7 different troops. As there are exactly 7 battlefield slots in large cities, and because diffrent types of troops cannot share slots, this will make the battle go longer than if you simply had 7 steam giants in defence. When a first breach in the wall is made a single steam giant will step in. He will hold off the enemy hordes at bay for one round. Then in the next round a hoplite and a swordsman will fill in 2 gaps in the wall.
Using the rainbow often ensures the battle going on for 3 or more rounds. In any case it is always useful to have 1 spear man and 1 slinger behind every wall. Even a level 1 wall with 1 spearman behind it will ensure the battle going on for 2 rounds. This will cost the attacker a loss of 15 minutes. And time is the most valuable resource of all. Be it a MMORG game or real life.
In my mobile colonies I use a level 1 wall, that I periodically demolish and rebuild as required. I demolish the wall when I move the army in, and rebuild it when the army leaves. The wall level also affects the garrison limit. An exact formula can be found on Wikikariam.
The wall therefore is an optional building. It should only be built if you don't know what else to do with your wood and marble. In the past versions of Ikariam the wall gave defence bonus percentage for every level, and in Evony the wall gave extra range to ranged units - those who shoot. But in the modern version of Ikariam the wall is a waste of building materials.
Ikariam Town Hall
Do you know all the Secrets of the Town Hall in Ikariam? I sure wish I did. Obviously Town Hall is an essential building, no Town Hall, no town. The higher the level, the more citizens the town can have, and the more action points the town will have. Level 1-3 Town Halls grant 3 action points. There will be 4 action points in level 4-6 cities. An allied or occupying troops will have just 1 action point in 1-3 level cities. An action point is how many actions you can have going on from that city simultaneously -with 3 action point you can have a cargo shipment going out of town, troops moving to another city and a navy moving out. Or you can launch a 3 wave attack. This is a very important and often overlooked issue. Many armies become stranded in an occupied town that has only one action point - once your boats loaded with pillaged goods sail home, the army cannot move anywhere else, unless you use a special recall button, and then they return all the way to a distant home city. And this may not be what you want. So you may take a chance an leave the army in an occupied city overnight, without relocating it first. Sometimes you don't find your army in the morning, because the enemy found it first.
Ikariam Spy House Hideout
This building is only useful for small players on a new hotly-contested world. For large players on an established world it is advisable to have a single level 32 spy-house to use for aggressive spying on other players.
Contrary to the official Ikariam game guides it is best to demolish the other spyhouses as soon as possible and use the space for something more useful.
Ikariam resource boosters: winery, stonemason, forester, alchemist's tower
These building are very cheep at lower levels, but after level 25 they become prohibitively expensive. The way to utilize them best is to use them as temporary buildings to be built early on in a new town and demolished later to get four warehouses when you go for the eleventh and especially twelfth cities. These buildings are invaluable early in the game. After you get your coveted twelfth city you may consider rebuilding the glassblower - if you wish to get heavily into science research, or the alchemist's tower - if you are a dedicated warmonger.