How Do I Get EMPs, Nukes, And Other Warheads?
A: All of these can be built at the Missile Silo, a very expensive Constructor unit. Each player can only build a few Missile Silos, so be mindful of where you build them. The Missile Silo can be found under the CONST tab of your command station. Be aware that all of the warheads come with an AI Progress cost, which can be pretty significant. Built and use warheads with care!
On the bright side, the AI does not have or use warheads at all. It has a variety of core ships that humans can never build (only capture with parasites), but warheads are the unique humans technology.
How Do I Use Nukes?
A: Nukes are the most powerful warhead in the game. Detonating them has the negative effect of raising the AI Progress by 50 (in addition to any AI Progress increases that are incurred based on what you destroy). They also destroy all resources on the planet, and block supply on that planet forever. Be very careful with these, having one 'accidentally' go off on a friendly planet is bad!
So, those are the negatives about nukes... why the heck would you want to use one? Well, when one goes off, it completely destroys all non-core, non-starship ships at a planet. This is something to only be done with care, but it can really be a lifesaver in some situations, where the AI is incredibly entrenched and you cant get any momentum otherwise.
Nukes can be set off on your own planet. Basically, there are two ways to set off a missile -- scrap it yourself, or have it get shot down by enemies. If enemies are on your planet and happen to destroy the nuke, there goes your planet and all the resources and ships on it. Your home planet command station is immune to nukes, just like core ships and starships are, so those will at least survive (you won't lose the game immediately just because of one misfire, in other words), but it is still a VERY costly mistake to make.
Be especially careful with the higher-level nukes; those dont just destroy the planet they are on, but the adjacent ones as well! Very doomsday like indeed. Try to avoid these.. but they can be great fun if you dont care about the consequences.
So, given all this, nukes come with a little in-game warning that only advanced players should try to use them. Nuking a whole planet out of existence is great (morbid) fun, but the potential repercussions can be pretty dire. Just as in real life, firing a nuke is not something to do casually.
How Do I Use EMPs?
A: Compared to nukes, EMPs are a much more casual affair. They don't have any negative consequences other than a minor AI Progress increase.
Setting off an EMP at a planet will paralyze all non-core, non-starship ships at that planet (enemy ships, your ships, and allied ships). This makes space docks and starship constructors pause in building, it makes all affected ships unable to fire or move, it reveals all cloaked ships, it temporarily disables all mines, and it temporarily takes down all force fields. These effects last for about thirty seconds or more, depending on the mk level of the EMP.
There are a lot of potential uses for EMPs, but the best are in concert with starships or with a fleet waiting just on the other side of a nearby wormhole. Once the EMP has detonated and paralyzed all the enemy ships, bring your fleet in and use the brief window to accomplish whatever needs doing. This is a great way to take out a force field that has a lot of high-level ships under it, for instance (in those situations, it can sometimes be very tricky to take out the force fields with bombers alone). This can also be used as an effective way to do a gate-raid on a planet that otherwise has too many high-level ships.
So EMPs tend to be way safer to use, but a lot trickier in most circumstances. They definitely help as a siege-breaking tactic, though!
How Do I Use Lightning Warheads?
A: Lightning Warheads are the least-expensive warhead, and they also pack the weakest punch. When a lightning warhead is set off (by being shot down or by being scrapped), it emits a single blast of lightning that does heavy damage to all ships in its range. This is like a very powerful one-shot Electric Shuttle or Lightning Turret. They generally excel at taking down clumps of fleet units, or destroying high value targets. Similarly, you can pretty much obliterate whatever is waiting near the other side of a hostile wormhole by sending a lightning turret through. It bears noting that the range of the Lightning Warhead is fairly small, so it is a much more localized warhead than the nuke. The Lightning Warhead has the advantages of only costing trivial AI Progress upon detonation, though, and also the advantage of working just fine against core ships and starships. Both warheads fill very different strategic niches.
How Do I Use Armored Warheads?
A: Armored Warheads are virtually identical to Lightning Warheads (see above), except that they are almost completely indestructible by enemy forces and they cost vastly more. These are the most expensive warhead in the game for good reason -- they are an almost foolproof way to do a gate-raid. Just be careful that the enemy command station is not in range when the warhead goes off, or you might unleash the hordes of enemy ships that you presumably build this titanic warhead to avoid.
Armored Warheads are very useful for doing strikes against targets deep in enemy territory, or against very large groups of starships that might shoot down (and thus set off) a lightning warhead before it gets in range to actually hurt the bulk of the starships. Still, armored warheads are so expensive in terms of metal and crystal that their use is almost always going to be a last resort for most players.
How do I use tachyon warheads?
A: Tachyon warheads serve as a strategical method of decloaking all units on a planet. To use, select a tachyon warhead produced from your missile silo, and self destruct it on the planet you need things decloaked on (use the delete key). This means that any cloaked units on that planet will become uncloaked for the time listed on the warhead, corresponding to the mk level of the warhead.