That's tricky stuff, start by playing with "pathfinding behavior"

You would have to give them decision variables, to give an impression of A.I and create some randomness to their actions...

You tend to centre the camera on the player and scroll the play area to suit, but there are no rules, if you can think of a different approach, then go for it,adding scroll to behavior to the player will keep him central to the screen.

That white box in the editor is your layout, levels tend to be inside these, but you could have a level larger than that, see unbounded scrolling, Your view port is the visible play area at runtime

JoshWegener welcome to the forum....Nice medal ya got there!... <img src="smileys/smiley2.gif" border="0" align="middle" />

— I know layers are not exactly the same as the z order, I said as long as there is no parallax happening, I meant from a graphical point of view and for the purpose of the example given it would work...

Joskin told him how to do it using families on page one...

Yes you would have to move the player to layer 1, but I don't see why that is an issue...

If your sure it won't work, I'm sure I don't know exactly what it is your trying to do, moving between the layers is just the same as moving up and down the z order, unless there is parallax scrolling involved it should work...

If you set unbounded scrolling to on, then the layout boundaries will not stop the scroll and keep in cental at all times, but failing that create an invisible sprite that acts as a camera attach and detach from your player when needed and set scroll to camera when needed rather than your player...

This is much easier with layers create two more layers, set your black wall to layer 1, the blue to layer 2 and your done, then changing your player from layer 0 (farthest from camera) to layer 2 send to top (nearest) when needed will mean any other objects added in future can just be placed on the correct layer without needing constant overlap checks

I have just posted a tutorial, that may help...

scirra.com/tutorials/565/beginners-tips-to-using-global-variable-for-lives-with-lives-indicator

I have had this also, luckily i just reloaded an older save and lost 20 mins of work...

I think it's looking for a temp directory that your project is stored in when editing, If you have system cleaning software sometimes this can delete files in this directory I believe, do you not have a recent back up, to go back to?...

You want a round pixel ?...good luck with that one...

Oh forgot to add, pressing fire sends my browser screen skywards, not good as I could not see my enemy position indicators...

Pretty good, if you like this sort of thing, few things I noticed

Against the smooth scrolling and slick HUD the enemy movement seems very clunky and gives them a cardboard cut out look, I think it may be due to using sprite animation rather than rotation for their movement...

Also the enemy just appear right in front of you rather than see them in the distance...gives a very cramped feel in a vast universe

Collision detection was a tad iffy and something that would probably bother Sci fi game fans (Your audience), is your shots hit exactly in the centre of the reticule, irrespective of movement, where in reality you would need to take the time for the shot to travel into consideration...