Intro:
This is the way that I beat the impossible difficulty level with "Domination" as the victory condition. I'm not saying it's the only way, or even the best, but it works pretty well for me. I assume you have a basic understanding of the game going in, so I don’t explain many of the terms, etc. I welcome comments, but be nice, it’s my first attempt at a guide. And it’s not like I’m getting paid or anything…

Part I

Factions and Leaders: I choose “Supremacy “ and “Soohua.“ The free wonder and the tech upgrades are more important to me than other bonuses. Perhaps you will get lucky and get some key upgrades.

Science upgrades (research technology): Focus on getting your fighters, torpedoes, and engines upgraded, in that order. Figure level 3 in fighters, 2 in torpedoes asap. As the upgrades start getting real expensive, I spend some on a level 1 or 2 stealth, and maybe 1 in shields.

Later, as the game progresses, continue this path using the order of importance above and you should be alright. High level torpedoes are devastating, I’ve seen hits cause over 1000 damage. A direct hit with a torpedo level 3 or higher should be a one shot kill against any ship you will ever face.

A trick here; look for planets that give free tech upgrades. Use the upgrade on the most expensive tech (this should be fighters). If the planet is neutral, send your fleet there, complete the mission, get the tech, and then leave. Now do it again – and again. This saves a ton of money.

The Market: I only look at this if I need a few bucks to repair a ship, or maybe if I’m just short of the metal needed to buy a wonder. Sell food first. I never sell energy – it’s too valuable.

Diplomacy: I ignore diplomacy completely. When the screen pops up, I just pick the last option (I have other matters to attend to). There may be good stuff there for those who enjoy that part of the game, but it’s not for me.

Planet upgrades: These are pre sorted for you in the perfect order, the most important at the top. Upgrade going down the list. I upgrade planets in the following manner: Start with the planets furthest from the enemies. Of course this is impossible in the early stages, but does come into play as the game progresses. Since each upgrade in a category gets progressively more expensive, I upgrade all the planets with level one before moving up. Actually, my games go so fast (med/large maps) that I often don’t get past level one or 2 in many upgrades. Energy, followed by metal are the most important and first to be upgraded. As far as planetary defense, I only use this on the planet that has reactive armor (which I dare not lose). More on this later. I don’t bother with warp nodes, but on an epic map, maybe you should. Note that you lose if you lose the home world, you lose the game, but it starts with planetary defense.

Part II
Wonders: The most important wonder (by far) if you follow this strategy is “Reactive Armor.” But don’t waste your time building it, the object is to make sure nobody ELSE has it. Reactive Armor is Kryptonite for this strategy. Reactive Armor makes ships immune to torpedo attack, and if your enemy has it, your first objective, above all else, should be to take it and keep it secure. I played a game (on medium difficulty) and the AI had the planet with the wonder.
Took me 3 invasions to get it, and I had a very difficult time finally winning the battle. I finally won by causing him to split his forces, then using everything I had, including massed high level fighters, to take down the ships one at a time. Quite rewarding when I finally won, but not something you want to have to do on a regular basis. If your enemy has reactive armor, instead of still upgrading your now useless torpedoes, change your tech upgrades to all fighters, stealth, armor, and shields until you rectify the situation.

The wonder you want for yourself is “duel command.” This allows you to launch 2 torpedoes (or fighters) instead of one in a turn. Last game I played, I took out 9 enemy starships on the second turn of a battle. A spread of 10 torpedoes will do that for you.

The next most desirable wonders are “intelli-shields”, “cloaking”, “hyper launch”, “stealth torpedoes”, and “torpedo boosters” (in that order). I like all around shields because my ships are usually running from the enemy. With the hyper launch wonder, fighters become quite a bit more effective on their first turn. Jump start is also nice to have, get those torpedoes out before he moves.

The other wonders such as the ones that buff lasers and canons have little or no use with this strategy.

Ship builds: On impossible difficulty, I have found that the ai ships are so much more powerful than mine (especially early on) that there is simply no hope of standing toe to toe and slugging it out with them. Here I am flying around in ships with 80 hp and the computer ships have more than triple that. So I realized that building lasers, armor, and the like was clearly not going to do the job with my style of ignoring diplomacy.

I decided to base my ships on torpedoes and fighters. You are also going to want level 2 or 3 stealth as soon as your ships have their fighters and torpedoes. And make your ships fast (better for running away). Think of your ships as aircraft carriers, launch the weapons and fighters and keep your distance from the enemy. Your ships are not designed as brutes that can slug it out.

I use 1 ship until I can afford a second at mid game stats. By the time I can afford a late level ship, I will have about 5 ships. I haven’t built over 5 in a game.

I don’t worry much about lasers, cannon, and sensors. I do put some money into shields and armor, but the priority is fighters, torpedoes, and speed. And some stealth.

Typical early ships: 4 torpedoes, 4 fighters, level 1 stealth, and level 3-4 speed. On the first turn, all I’m doing is adding fighters and torpedoes. The rest comes later.

Typical mid game ships: 5 torpedoes, 5 fighters, 3 stealth, 4 speed, 1 laser, 1 cannon. Shields and armor 3-4. The laser and cannon are just for defense against enemy fighters that get too close. The AI typically uses low level fighters with 15 hp, so level one is plenty to deal with them.

Typical late game ships: (my games last less than 15 turns): 6 torpedo, 8 fighter, 3 stealth, 6 speed, 1 laser, 1 cannon. Shields and armor are as much as you can afford.

Part III

Battle tactics. First turn of a battle: If your fleets are VERY far apart, launch as many fighters as you can. Keep the fighters distance (and tuck them behind planets and asteroids) from the because they will just get picked off one by one if you attack. You want a bunch of fighters out before attacking so that you can overwhelm the enemy (who is hopefully being chased by torpedoes as well). If your range is within torpedo range, launch your torpedoes instead. Move away from the enemy. Split your forces 3 ways, right, left, and straight back. But the right and left detachments should be moving away, not straight to the side. Turn 2 is a repeat of turn 1. If the enemy is close and you have the wonder “dual command” use one of your action points for stealth every turn. If you have cloaking, don’t bother, it’s already on.

Once I’ve whittled his units down with torpedoes, or he has closed the range enough to make torpedoes less useful, start launching fighters. Expect to lose lots of fighters. Hopefully, yours have been upgraded with more hit points (modules), but either way, expect them to die. That’s ok, the enemy is shooting at them instead of your starships, and as long as they are giving as much as they take, you will be ok. Use fighters in mass. Attempt to fire from behind the enemy ships where their shields are weakest. Use your fighters to keep enemy fighters off your starships by having them as far as possible from your main fleet (that way, it’s easier to flank).

Try to use your fighters on the weakest enemies first, while your torpedoes go after the tougher ones. Be careful with fighters against really powerful ships. You must have upgraded fighters to attack them, and you need a bunch at a time, otherwise, they will just get slaughtered. Remember that once your torpedoes are gone (or ranges are too close) your fighters are your only offensive weapon. Don’t waste them. I’ve had many battles where 10 fighters (the max you can have at a time) all fire at the same enemy for several turns before finally bringing it down. Be careful with torpedoes, yours will blow up your fighters as well as theirs (which on occasion might just be worth the sacrifice).

Your battles should consist of you running from the enemy while launching torpedoes and fighters. And keep stealth going as much as you can.

Part IV

Random tips:

1. Its much better taking an enemy controlled planet than a neutral one. Not only do you deny them resources, but you get the planet immediately, rather than just moving up a level of influence.

2. Once you get the planet that has the wonder “Reactive Armor,” build as many planetary defense levels as you can. Other than that one planet, the only other place I might build them would be the home planet.

3. This is a big one that I learned the hard way: Try to save as much energy as possible for ship repair to be used during the middle of turns (yours or the ai’s). By the time you have reached mid game, and preferably before, have at least 200 for each ship. More as the game progresses. This is very important. I played a game where my fleet was demolished, and I had no energy to repair them between battles (all one turn of the ai). So the ai just walked through my whole empire. At least if you can repair, you get another chance to fight with functional ships during his next attack. It is a balancing act, you want to spend all the energy on making your ship(s) as powerful as possible, but if you have no reserve for repairs, you are really rolling the dice. Best case scenario, you have to end your turn early after receiving some damage (or outright losing a battle). Worst case, game over. Remember in a pinch that you can sell resources at the market and buy energy, but if you are out of that as well, then you can be in real trouble.

4. Don’t put fighters in the same hex. I’ve seen more than one destroyed with one shot.

5. If one of the AI has the “Reactive armor” wonder well behind the lines, consider fighting the other ai first. Get lots of energy to max out your ships before you have to try to pry the planet with the wonder from the enemy. This might be a good time to try diplomacy, keep that faction away from you until you are ready.

6. Battle cards. Use these, as they are lost if not used. If you have the one that says 25hp sabotage on enemy fources, wait and use it when he has fighters out. If you have the one that increases shields or speed, use it on the ship closest to the enemy, or perhaps your main ship. If you have the jump gate card, save it for a cornered ship.

Following this strategy, I generally win on impossible. The times I have lost, it’s been because my fleet was destroyed and I had no energy to fix them before the next attacks.