22 2 10From the main menu, select "Start", select "Arena I" when it loads, you will be in front of the "Reactor" where you can buy weapons and upgrades. Press LT to access the upgrade menu then use the D-pad to select the Rifle and press A to buy it. Press LT to exit the upgrade menu. Press RB to switch to the Rifle and we are good to go.Now press RT while in front of the Reactor to start wave 1. Shoot all the enemies until you have completed the wave and then rinse and repeat the RT at the reactor to start new waves until you kill enough enemies to unlock the achievement. Should take about 2-3 minutes.Guide not helping? View 1 more guide for this achievement.Showing most recent comments. View all comments. This bugged out on me and this solution fixed it, thank you!Posted by eohjay on 07 Jan 21 at 16:45 Had to delete the save file and uninstall / reinstall the game to get this to pop also. I then followed this guide to the letter and first attempt. ThanksPosted by Gloss666 on 27 Jun 21 at 09:39 Thank you this worked for mePosted by KTLDC on 12 May at 20:09 Leave a comment