Here is the full list of all 27 G Prime achievements worth 1,000 gamerscore.
Finished a level without using any rocket stages.
Finished all levels in the sector "The Path Less Taken"
Read more than 100 eManuel articles
Got a missile 990dr or more away from the station and then ping a target
Finished all levels in the sector "... And Through the Woods"
Finished all the levels in the sector "The Rain"
Pinged a target at a distance of less then 10dr
Got a missile to come back and strike the station.
Got the missile to go faster then 1360dr/sec
Finished all the levels in the Sector "Sea Trials"
Got a rocket within 100 dr of two iceteroids.
Got the missile to go faster then 1020dr/sec
Got the missile to go faster then 680dr/sec
Found a perfect path in any level of GPrime
Got the missile to go faster then 340dr/sec
Unlocked once the player has fully watched each sector cut scene
Finish all the levels in the sector "Enigma"
Finish all levels in the sector "... Hitchhiking Down a Long and Lonesome Road"
Finish all the levels in sector "Nothin' But Net'
Got Silver?
Get 10 perfect path awards in GPrime
Get 20 perfect path awards in GPrime
Get 30 perfect path awards in GPrime
Get 40 perfect path awards in GPrime
Get 50 perfect path awards in GPrime
Fire more than 10000 rockets.
Have a missile travel more then 100000dr and ping a target