well, on the start of the layout it is set to 50 and the corresponding animations are set as animations on a single sprite element, right?
OK
Playa on collision with enemy
subtract 25 from "Playalife"
This will make the playalife lose 25 points if the player is in collision with an enemy.
These next 3 events check the status and set the animation
system - compare variable
if playalife > 49 healthbar set animation to full
system - compare variable
if playalife = 25 healthbar set animation to half
system every tick - compare variable
if playalife < 1 healthbar set animation to empty
---playa - destroy
Sorry aboy my syntax earlier. :)