What are the best modules to pick?
Modules are not as important as they were in the first version of MOG, but they are still useful, and some are better than others; in particular, there are three that are at the top of the list: Instant Repair, Projectile Size, and Emergency Repair.
Instant repair is passive healing and removes the need to pick up hearts if it’s leveled high enough. Because of its immense power, this module is much rarer than normal ones and is ranked the highest on this list.
Projectile Size makes nearly every single weapon in the game better by letting them hit 2 or 3 times when they would have only hit once, practically doubling their damage against large groups.
While this is very strong, it becomes hard to see the enemies and their projectiles because your bullets are so big, so keep that in mind when taking it. 2 weapons are not affected by Size; these weapons are Homing Laser and Energy Robot. (Homing Laser is still one of the best, even without this buff.)
Emergency Repair isn’t as important because of EX Upgrades, but it’s still very useful. An extra life can go a long way and might just win you a level.
As for the rest of the modules, both of the Purple ones are three modules combined into one, so taking those are always a good idea, as are the POW and Attack speed upgrades, which are weaker versions but are still very worthwhile.
Another module to look out for is Movement Speed. The reason for this is that many of the late-game bosses and enemies are much faster than you and do insane contact damage. (This is mainly for the Challenge modes, but it’s still really useful elsewhere.)
There is only one module you should be actively avoiding, and that’s Signal Amplification (Magnet). It’s bad at every stage because collecting the drops on the ground is rarely a problem.
Every other module is Medium; they are all good in their own right, but you should probably only take them if you already have the ones you want. Chances are you are going to get Defense and Max Health. When these are paired with a Revive or Passive healing, they can become very strong.