(Input Lag / Input Delay Fix) How to Fix Control Delay in Online Co-op Repentance+

You need to own all the official DLCs for The Binding of Isaac: Rebirth:

• The Binding of Isaac: Rebirth
  
• Afterbirth
  
• Afterbirth+
  
• Repentance

After that, you will automatically get the free Repentance Plus DLC, which enables online co-op.

• Launch the game.
  
• Go to Options.
  
• Scroll all the way down.
  
• Find the Input Delay setting.
  
• Set it to the minimum value.

I don’t know how long this option has been there, or why input delay isn’t set to the minimum by default. A few months ago it didn’t even exist. My wife and I bought Isaac, realized we had to buy all the DLCs to unlock online co-op, so we did. We played for about a week, ~10 runs, and it was fun, but the delay was too annoying to keep going. Recently we decided to check if it was fixed — nothing had changed, and there were no mentions of it in the patch notes. Out of curiosity I went digging in the settings, and that’s when I found this hidden option.