- The player is able to jump/spin jump on bullets:
- Spoiler

- Birdo should resist three hits by a bullet, not only two.
The following NPCs has the same problem in common: they can't be hit by bullets in a row. I don't think it's directly related to PiercingDMG since when I disabled it I got almost the same result.
These NPCs should be get hurt by bullets NPCs continuously, plus, the bullet should die after colliding with the enemy:
- Boom Boom
- Bowser (SMB1)
- Bowser (SMB3)
- Larry Koopa
- Ludwig Von Koopa
- Breakable Glass (npc-208)
Example:
In 1.4.5, Bowser only can be hit every two bullets (and both Mario and Bowser are stand still, it's even worse when you're running towards him since he ignores even more bullets).
- Spoiler

In SMBX 1.3 however, Bowser gets hurt by all bullets:
- Spoiler

Suggestion: Make Boom Boom die after 10 bullets (instead of 3) and make every bullet dies after hits him. This doesn't happen in SMBX 1.3 but it's a more consistent interaction between bosses.

