Spend quality time with Gat
Go to the Broken Shillelagh to start this quest. You'll be inside Genkibowl with Johnny Gat. You just need to keep killing and chain your kills to score more. You still have your health bar so avoid taking too many damage until you get your powers back.
In the next area, you'll be introduced to murderbots as well. Use your RPG and powers to take them out. You can also throw mascots to the green circles for extra points. It will help setting your Telekinesis to life steal to replenish your life as well.
For the last stage, continue forth and take out the powered genki girls along the way. When you're near the end of the stage, you'll have to fight the Syndicate's boss. Use your buff and get near him to ignite him on fire. Then, you can make him eat lead helplessly. Just activate Buff again to kill him without too much resistance.