   Levels and spawning in a space shooter
  I have been trying to figure out how to do this in my 2d space shooter(1942 syle). So far, this is what I do:I record the total distance covered by the player and spawn new enemies basied on the distance covered. When they are spawned is defined in the level file. For example, a file containing "800" and "1100" will spawn enemies when the player has covered a distance of 800 and 1100.Now, I was wondering what would be the standard way to do things in these games.Would a tile engine be used?   
  I've never done that before but my guess would be they do it either the way you're doing it (which is, essentially, time based) - or set it up so each wave spawns a certain amount of time after the first has been cleared.  I don't think tiles would have much to do with it, unless it was a tile-based shooter of course!   ;  heres an entry from mine<EVENT type="addvehicle" time="1.85"><ALIEN type="orange" pos="130 0 130" dir="0 1 0 0" vel="0 0 0" fp="arrive1"/></EVENT>each loop check to see if a certain critera is met (int the above is if the level time > 1.85secs then it spawns)   ;  Shooters are interesting. They can be very simple, or complicated depending on what you want to do. Enemy attack patterns, following curves, etc. It would be great to see more information on developing these styles of games. Also, you may want to check out http://www.shmup-dev.com. It's a forum devoted to developing shooters.   ;  I used a camera/tile system to spawn enemies.http://rel.betterwebber.com/index.php?action=contents&item=Space+Impakto