If the action gets too intense in UNDER NIGHT IN-BIRTH II Sys:Celes, you may end up accidentally hitting the pause button (which is the Options button on the DualSense/DualShock 4 and the + button on the Nintendo Switch). This will end up throwing the rhythm and the intensity of the fight completely off.
To see how you can prevent accidental pausing in this 2D fighting title, you can check out this guide at Seeking Tech.
1. From the main menu of UNDER NIGHT IN-BIRTH II, open Options.
2. Next, you need to select Game from the Options screen.
3. In the Game Settings menu, move the cursor down to In-Battle Menu (Versus Mode/Network Mode). You should see the following description appear at the bottom:
Change the length of the button press required to open the menu during a match.
4. Make sure that the In-Battle Menu (Versus Mode/Network Mode) setting is set to On and then exit the Option menu.
To now pause during the middle of the match, you need to hold the pause button. If you quick press it instead, then the battle will keep going.