This is a screenshot of the One Little Rat mod for Sonic Robo Blast 2. As noted on the left side of the screen, the rat has three status effects, with fairly self-explanatory names. The numbers next to them can go up to 10 and denote how much of that status effect you are. Getting to Drowning status 10 will result in death, while Cold status 10 or above will result in rapidly taking damage. Wet status does nothing on its own, but can affect other things. For example, getting wet in a cold area (like this one) is a bad idea, but it can reduce incoming fire damage (though the latter has yet to be implemented).

On damage, there are two types: bleed and true. True damage results in an instant loss of health. Bleed damage is damage you take over time, rather than all at once (though, if you take bleed damage in excess of your health, the excess is converted to true damage). The medikit item will remove a large chunk of bleed damage, though it will not affect bleed damage that has already been deducted from your health. Items that restore your health rather than removing bleed damage are rarer.

Many attacks deal a mix of bleed and true damage, but this is not always the case. For example, an electrified floor will not deal any bleed damage.

On another note, in case you're wondering what this strange place is, this screenshot, along with the inventory screenshot, was taken in the debug room I made for this mod.