BHero JP Temp v0.1

No firepower in battle room path (minimal)
Go to Heavy Room (about 5 seconds saved)
Sky Room card key box (about 1 seconds saved)
Dragon Road graveller takes 3 hits instead of 5 (5 seconds)
Nitros takes 5 hits (11.5 seconds)
1 enemy missing in Great Rock (1 second)
Endol takes 6 hits. (12 seconds)

Maintain powerups
Erars Lake - wall through off to side (3 seconds)
Waterway - no spikes at end (1 second)
Rock N Road - no bomb in way, door takes 3 hits (4 seconds)
Warp Room - no wall through necessary, do purple warp glitch to save lots of time
Dark Prison - no bomb (0.5 seconds)
Nitros takes 5 hits (11.5 seconds)
Baruda takes less hits. (18 seconds)

Maintain powerups
Magma Lake - Health at beginning, no enemy at beginning, no bomb at end I think? (1 second)
Magma Dam - no need to hit refresher due to hearts (2 seconds)
Crysta Hole - no spiked platform at end (0.2 seconds)
Death Temple (no enemy at end) (0.2 seconds)
Death Road - no bombs, door takes less hits (6 seconds)
Float Zone - less bombs, actually takes slightly longer probably. (+3 seconds)
Nitros - takes 5 hits. (11.5 seconds)
Hard Coaster - have to ride second platform (+11 seconds)
Bolban takes less hits (15 seconds)

Hopper Land - jutting ledge (0.2 sec)
Junfalls - Platform Height (0.1 sec)
Snowland - Enemies not in way (1 sec)
Snow Circuit - electric guys not in way (1 second)
Heaven Sky - boss takes less hits (8 seconds)
Eye Snake - less enemies (0.2 seconds)

Air Room - CD more convenient - 0.3 seconds
Zero G Room - no switch bomb - 5 seconds?
Natia - Cronus takes way less hits (18 seconds)
Reset after W4 for no penalty (8 seconds)

Endol takes less hits (18 seconds)
Baruda takes less hits (20 seconds)
Cronus takes less hits (10 seconds)
Nitros takes less hits (11.5 seconds)
Bolban takes less hits (14 seconds)
Natia takes less hits (10 seconds)
Bagular takes less hits (40 seconds)

A 50:00 US is probably a 44:XX-45:XX JP
Warp Room JP trick:
You can go in and out of the purple warp, then jump down and hold left at the last second to grab the far side of the gate, then jump to the exit.