How much health do you have at each level in Bastion?
According to the PlayerUnits.xml file, your character starts off with 51 health, and then you receive +2 health for every level, up to level 10:
Level | Health
----------------
1 | 51
2 | 53
3 | 55
4 | 57
5 | 59
6 | 61
7 | 63
8 | 65
9 | 67
10 | 69
Besides the health you receive for leveling up, you can also add an additional 10 health at any time by equipping the Squirt Cider spirit.