A number of the achievements - namely the ones about completing masteries -are sadly quite grindy.
If you don't conciously work torwards them from early on, you can easily run out of game before you've done them all.
The fact that you can't repeat the finial mission to finish those grinds doesn't help (to clarify: You can repeat the last mission, but after the end credits the game gives you a save from before starting the finial mission to load, so all progress from that mission is whiped).

Originally posted by Bird_Dog:

A number of the achievements - namely the ones about completing masteries -are sadly quite grindy.
If you don't conciously work torwards them from early on, you can easily run out of game before you've done them all.
The fact that you can't repeat the finial mission to finish those grinds doesn't help (to clarify: You can repeat the last mission, but after the end credits the game gives you a save from before starting the finial mission to load, so all progress from that mission is whiped).

That's helpful, thanks. So can you go out and do random stuff BEFORE the final mission to get all mastery stuff?

There isn't much in the way of repeatable stuff.
Some random enemy spawns, but only small ones and infrequent.
Your best bet is to identify a situation in a mission where you have enemies spawning infinitely and gind out some masteries there.

There's a mission in the second star system where you attack a cult forward opperating base and Forsa advises you to target the launchpads first. If you leave them intact, enemy fighters spawn forever and you can grind out some stuff. Particulary Drift trance mastery and Boost mastery, and the masteries associated with the rite of the hunt.

Another good opportunity is a mission in the third system where you are to liberate some allied capital ships.
At the start the area is surounded by floating "towers" with launchpads. Good place to grind out the masteries associated with the storm rite.

also keep an eye out for "sniper" Turrets and Ravens and Vultures with the charging shot attack to grind out the Dodge Roll mastery.

Thanks for the help! I'll definitely watch out for those.