To achieve 100% completion in Halo: Spartan Assault, you may want to grab all these accomplishments, one by one...
Overrun - 10 Points
Complete Operation A
Switched On - 10 Points
Complete Operation B
Switched Off - 10 Points
Complete Operation C
Evacuated - 10 Points
Complete Operation D
Terminated - 10 Points
Complete Operation E
Escort Service - 5 Points
Keep all Wolverines intact in Operation A, Mission 3
Nowhere to Hide - 10 Points
Prevent all Jackals from regenerating their shield in Operation B, Mission 3
Never Knew What Hit Them - 10 Points
Kill a convoy target with every stationary gun in Operation C, Mission 3
Brute Force - 10 Points
Finish the objectives using only the Brute Shot, melee and grenades in Operation D, Mission 1
Foot Soldier - 10 Points
Finish the objective without using any vehicles/turrets in Operation E, Mission 4
Recruit - 5 Points
Earn a star of any type in an operation mission
Prodigy - 5 Points
Earn your first Gold star in an operation mission
117 - 20 Points
Earn all Gold stars in all operation missions
Distinguished Service - 15 Points
Earn all medals in the game at least once
Weapon of Choice - 5 Points
Score a kill with every handheld weapon (excluding Rocket Launcher and Spartan Laser)
Powered by MJOLNIR - 10 Points
Use every ability at least once (excluding Overshield and Seeker Drone)
Skull Combo - 10 Points
Complete any mission with the maximum number of Skulls active
Vidmaster Challenge - 15 Points
Complete Operation 5, Mission 1 with the Hollow and Black Eye Skulls active
Extra Credit - 10 Points
Complete 75 challenges
Pension Plan - 10 Points
Earn 25,000 Spartan Points throughout your career