Does anybody know how I can make it so the "aliens" every 3 seconds are placed at a random position just outside the playfield? And then walk into the playfield?
The picture link above should help explain what I mean...
I can't see the picture either. You could make a bunch of "alien spawner" objects outside of the playfield (set to not follow scrolling). Then,
Every 3 seconds + pick one "alien spawner" : create alien at (0,0) from "alien spawner".
Alien's Flag 0 is off: alien look at center of screen or player (just to get it initally in the playfield), set flag 0 on.
"Omg. Where did they get the idea to not use army guys? Are they taking drugs?" --Tim Schafer on originality in videogames
create one at the top (-50 of the Y axis so it will be above the top of the viewable screen) then choose a random position along the X axis - random (320) - i'm assuming your window will be 320 pixels wide. The make its direction down or whatever so it will walk on screen.