See the ReadMe for more details on the Mission Difficulty scaling.
The original difficulty mod actually went up to 5x for testing, but I’m not sure if anyone’s beat both campaigns on 2x or 3x yet without using the retire trick. Such challenges are possible in skirmish however: https://www.youtube.com/watch?v=eD5-I-GNong
To answer your other questions:
- Taiidan defense fighters shoot down missiles with their gun. They also have a small field just like a Taiidan field frigate. These fields block bullets, but not ions or missiles.
- Instant hit weapons are not affected by the fields, including pulsar corvettes, lance fighters, Vaygr cruiser side lasers, and Taiidan defense fighter’s laser.
- I think one field blocks about 75% of bullets. Some large bullets may have a better chance to penetrate fields (like Hiig Destroyer guns) but I forget.
- Two stacked fields block about 95% of bullets. Three stacked fields is about 99%, etc.
- Anything fired inside one field is not blocked. However if there are multiple fields, they can overlap and provide a stronger defense.
- See #2
- See #5