You'll have to be more specific with the bullet thing, unless its a image of a bullet you want on screen...
...about the Y axis, you could just use the LINE command or a sprite if needed. However, if you want to add this line so that it collides with the sprite and unables it from going off screen, you'd better do it throught code, such as...
create bitmap 1,10,10
cls rgb(255,255,255)
get image 1,0,0,10,10,1
set current bitmap 0
delete bitmap 1
y=100
sprite 1,s,y,1
do
if leftkey()=1 then dec s
if rightkey()=1 then inc s
if s>screen width()-10 then s=screen width()-10
if s<0 then s=0
sprite 1,s,y,1
loop
...that is just a quick example of how. The
-10 on the IF condition is because the image is 10 pixels width, so as to have it stop at the very end of the screen and be able to see it, if not it will stop once its upper-left corner reaches the border of the screen, and doing so will put the sprite off screen. Hope it helped someway....
