Drecrease life

I intend to decrease life, removing little sprites that represent players life. How to implemt it?

Thanks

you can make the amount of max lives, and set all the lives whivh are not in the starting to invisible, add a variable for lives, then add as many events as you need,

if [health] = 2     set heart1 visible

                    set heart2 visible

if [health] = 4     set heart1 visible

                    set heart2 visible

                    set heart3 visible

                    set heart4 visible

if player is on collision with enemy     subtract 1 from [health]

it's a bit messy but i can't thank of another way

Could I use a sprite with 5 frames (one frame with 5 images, other with 4, etc)and change the animation as played lost lives, for example? or it�s not a good solution?

it could be a solution but you need to change frame, not the animation.

It would be :

On collision with

               set frame to [FrameNumber]

Though it think that solution provide by Ash1221 is more flexible if you need to tweak your life. Using variable is important.