Just won this achievement today.
The islands with commanders on are marked with a flag. Make sure if you are about to lose or a commander gets killed that you press home and quit the game, this means you can reload without penalty.
Make it a priority to upgrade at least one unit to elite archers and if you find the ring of command give it to that unit. Devastating against most units and saved my arse many a time. Use them in combination with strong infantry. If the map lends itself to pikes for example if the only attack route is a path up to a cliff pikes can be lethal. But they must be protected from ranged units at all times as they are vulnerable to arrows. Make sure to purchase volley for your archer unit this is great at taking down hordes if used at the right time.
Also be aware that when you end a turn the shadow moves across the map toward you from the left. Make sure not to get caught by it as this is game over. It is fairly easy to avoid but something to bear in mind. It is best avoided by moving mainly horizontally rather than diagonally.
Personally I used two elite archer units and two elite infantry units on most of the later maps with pikes occassioanly if the map was right. A question mark next to an island marks an item, try and collect them and assign them to units, they are essential in the later stages.
The hardest obstacle you will face is the brutes with giant bows, they tear through your units and are a real pain. My best advice is to use an elite infantry unit as a buffer, their armour absorbs most of the damage and allows you to flank them with other units, archers are ideal but if not elite infantry will rip them to shreds at close range.
Finally be careful which islands you select, try to pick the ones with the most buildings on, these are represented by yellow squares. Avoid islands which have few buildings in you can as you want to gather as many coins as possible to upgrade units.
The tiers cost as follows:
- Standard - 6 coins
- Veteran - 12 coins
- Elite - 20 coins
Do not waste coins, try to pour them into the same units so you can make them as strong as possible.
Good luck and please drop comments if you have questions I check in regularly. If you must down vote me please explain why and give me an opportunity to rectify the issue.
As a result of a comment from Anxsighety I am posting two videos demonstrating some tactics on the game. As he quite rightly pointed out, I had not provided specifics on strategies. I hope this has gone some way to rectifying this. Here I explain multiple threats and the use of the elite archers in combination with infantry and pikes. In the second video I explain how to deal with the brute archers which are by far the hardest units in the game.
Keep the feedback coming please I will further improve this solution if needed. I do not take negative feedback lightly and will always strive to rectify my mistakes in order to help you guys.
The latest video gives a detailed guide on how to deal with the hardest units on the hardest type of map. It has not gone unnoticed that I have bad feedback on this solution. I hope my additions rectify this. Please drop comments. I have written many solutions most of which have overwhelming positive feedback. Please give me the chance to improve the solution with constructive feedback
People are reporting a new update and some concerns about a level restart option being checked voiding the achievements. I can confirm that having the level restart option checked DOES NOT avoid the achievements. Some very useful info from one of the devs has been posted supporting this and that the only criteria for the achievement is that the game checks all 8 commanders are alive at the end of the game. Thanks to healtti and seitzz for this information.