Array problem

BlitzPlus Forums/BlitzPlus Beginners Area/Array problem

You're right about that drawimage should be in the loop. I thought you should move the If..Then inside the loop:
For x = 0 To AlienCount
If gfxAlienOnScreen(x) Then DrawImage gfxAlienOnScreen(x),Alien_x(x),Alien_y(x) ;Draw alien on screen
Next 

But why are you checking gfxAlienOnScreen() ? Maybe you could use this:
For x = 0 To AlienCount
DrawImage gfxAlienOnScreen(x),Alien_x(x),Alien_y(x) ;Draw alien on screen
Next 

?