Let's say we start with equal Mana and Health and HP/Mana is 50/50.
I started the game and with the upgrades it was like this; I have 50 HP, 1st level +25HP, 2nd level +50HP, 3rd level +100HP = 225HP.
On top of that with +40 armor plate passive and -90 damage (Cathedral bell) 90+40= 130.
As a result, with my 225HP and 130 damage reduction, I went to the 4th place from the bottom on the map: +1 Bullet load, +30% Crt change, Dmg lvl 3 and guess what! I died with the first bullet :)