Here's my take on this :
1) Create a sprite
2) set a global variable named "ProgressValue" or anything you want
3) every tick => set height of "sprite" to "ProgressValue" (you can make something like *2, *5 or whatever to make the bar bigger than 100pixels.
4) if you want some color, just edit frames of your sprite to the colors you want, lets say green and red, and then :
5) Event : If "ProgressValue" < or = 25 => set Sprite animation to frame "1", where frame 1 corresponds to the color you want, in this case I would guess red.
6) Event : If "ProgressValue" > 25 => set Sprite animation to frame "0", where frame 0 corresponds to the color you want, in this case I would guess green.
hmmmm will try this one