Since the health is a float, yeah, it can create issues. A health of 0.000000001 is greater than zero, but that would almost assuredly be displayed to the user as simply 0, causing player confusion. The easiest solution is to have health and damage always be integers. A less great solution is to use a non-floating point decimal format. If such doesn't exist in your language, you can emulate one by having health and damage both always be integers, but move the decimal point over, say two points, when displaying to the user.