Birth by Sleep -Ultimate Mix- is an overhaul mod for the PC version of Birth by Sleep Final Mix.
The mods contains a lot of changes, but here’s a summary:

• Fully rebalanced bosses and enemies for Critical Mode*.
• Over 30+ musical tracks orchestrated or improved from original concerts or games.**
• Rebalanced game progression to make better use of previously optional elements.
• Tweaked game’s physics to feel more weighty and responsive.
• General improvements and nerfs to several commands and command styles.
• Miscelaneous UI changes like customized NPC text bubbles per world.
• New bosses added for post-game enjoyment.

* Not rebalanced for LV1 but should work decently.

** Music mod offered separately. Link below and inside the BBSUM zip.