While combat and missions play a very large part of Armored Core, one of the more distinctive and time-consuming aspects of the game is the NEXT customization system in which you built your NEXT from various parts and and tune its fighting capabilities in order to suit your preferences. Thanks to the wide variety of weapons and parts, you can build everything from a lightweight aerial combat skirmisher focused on short-range machine guns to a fortress on tank-treads that incinerates everything in its path with grenades and missiles. As I mentioned a few posts ago, there is a pretty steep learning curve for this complicated system, but it is very flexible and fun to play around with.
One of my favorite aspects of the system is the fact that the designers tried to balance out every part. There is no clear and simple progression from the weak parts to the strong parts, like in Square's Front Mission series (which has a very similar customization system, if a bit less flexible of one). Instead, the parts that may come pre-installed in your starting NEXT can be useful throughout the game. Every part has its advantages, but also has its drawbacks, which means that there are very few parts that are unquestionably better or worse than others (though there do seem to be a few, I admit). For example, even though the Moonlight laser blade is a rare part that has to be won from a dangerous opponent and has a potent mix of high attack strength and long reach that separates it from any other laser blade, it still has such a high weight and large energy cost that it is completely unsuitable for many kinds of NEXT, even some pure melee-combat NEXTs (like the one I often use). Because there are so many weapons and parts that are very good, but only under specific conditions and in combination were certain other parts, there is a very wide assortment of possible strong NEXT configurations.
The piecewise construction system of Armored Core NEXTs has its issues, though. You can only directly compare parts one at a time, so both comparing a single part against multiple alternatives and comparing entire NEXT configurations against each other in detail are fairly difficult tasks. I often find myself making alterations to a NEXT one part at a time and praying that the sum of the individual alterations leads to a net benefit. This gets even harder when comparing the effects of parts that interfere with or compliment each other, but don't share the same slot, like comparing hand-held weapons to integrated weapon-arms, or trying to manage the complex set of main boosters, side boosters, back boosters, integrated tank-leg boosters, and back or shoulder mounted optional boosters. In such cases, it can be all too easy for minor drawbacks, like a slight energy cost increase on each part, to slowly add up beneath the player's notice until it becomes a serious flaw with no easy solution. A lot of this could be avoided with a few additional interface options, such as the ability to look at you NEXT's full specs in greater detail and compare those specs to another NEXT's.
Still, I don't want to say that the game doesn't provide the player with any useful guidance on designing NEXTs. The game provides a very comprehensive library of NEXT designs that you can load and use yourself, including the designs for every set of parts with the same name (like the Tellus or Lancel), as well as one for every last enemy NEXT in the game. If you are having trouble creating an effective aerial combat NEXT, you can always load the design of a powerful aerial enemy, like CUBE's Fragile, and either use it directly or take it as the basis for a new NEXT. This is easily one of the best features in the game, really, since it both makes NEXT design a lot easier and lets you try out what it is like to use any of the NEXTs you have fought against in the game. Actually, I should probably try this out some more myself. I've been wondering how Otsdarva's Stasis handles...