You'll unlock new equipment as your progress through the game, the path you choose to take doesn't affect this achievement so just go with whichever one you want to, it's worth nothing though that other achievements do require you to play through all 4 paths of the game so you might find it worth while to start at the top and work your way down, but like I said, which path you choose doesn't affect this achievement!
Each path of the game is split up into 4 acts, each time you reach an act you'll RIG will get upgraded to the next level.
For more information on how to complete the game please see here;
Did anyone survive? in Dead Space: Ignition