>>2136320
Literally everyone ITT will recommend beating vanilla first. It doesn't even take long, and plus, vanilla is maybe 10% the length of the megamods. You can even mod it to add shit like shotguns, sniper rifles, extra maps, and base facilities. That said, Piratez is the most flexible if you expect yourself to fuck up a lot (proptip: play on difficulty 2), but it's literally a sequel to the vanilla game, so you'll miss out on a ton of references and jokes.

>>2136334
X-Files made me want to kill myself and everyone else by the time I finally beat it. The early game is fun in a cock-and-ball-torture sort of way, but holy shit does it become a slog during the late-mid/endgame.