1 has more charismatic voice acting
1 has more interesting level design
1 has Lieutenant Kasan Moor of the 128th TIE Squadron. They're the best of the best.
2 has really shitty level design and bad visuals which, despite its engine being way better and pretty fun, make it an unfun game to play. During my playthrough, I referred to the game as Ragequit Squadron, and decided not to full gold the game, which was fun to do with 1, which only really had 1.5 missions that were complete shit.
Space battles shouldn't feature ships that can't be spotted against the black background without a targeting computer that, by using it, hurts your chances to medal.
---"It is too easy being monsters. Let us try to be human." ~Victor Frankenstein, Penny Dreadful