I just wanted too add on, in order to take bloody bullets you need to take 2 health upgrades* and then you can take it, but it only grants +3 damage, so taking 3 sharp shooters (+1 dmg) costs the same amount of upgrades AND doesn't lose any max hp
*technically you can grab it in two with starting hp + 1 health upgrade, but then I requires 2 health upgrades every time you take it