Wow! I still vividly remember spending my early childhood years with friends running around the school yard pretending that we were piloting the Golden Condor!

I've finally spent a few hours getting some more work on this done - slowly it will creep towards completion

This looks great! Awesome work

By the way I wonder how feasible such game would be for the new color calc? (which uses the same processor/RAM/flash as the 84+SE)

Also multi buffering is a good idea instead of redrawing every frame. There are efficient ways of scrolling without redrawing the whole screen.

Currently the screen is buffered. The background is only drawn once (when the level is first loaded). This is saved to the video buffer. Then the sprites are drawn on top of that and the result is copied to the lcd. After that, the buffer is restored (the background with no sprites over the top). The next frame, if the player has moved towards a screen edge, the background is scrolled 1 pixel and saved to the buffer again, before drawing the sprites. So the background isn't being fully re-rendered each frame.

The scrolling itself is actually quite fast. What's slow is the drawing of the sprites, as they are all masked and also clipped if they hang off the screen. Because of this, the game runs substantially faster when there is just the player sprite on screen, but then slows down noticably when more enemies, bullets & animations are all on screen at once. To combat this speed change, the game is currently throttled back so that it runs at a maximum frame rate of around 29fps (according to WabbitEmu). That way, the speed reduction is less when there are lots of enemies, bullets & animations to draw (I'll have to do some testing when I get a chance to get exact figures on the speed changes).
EDIT: I just ran a few quick tests. If I run the game at full speed unthrottled with only the player sprite on screen, it scrolls on average at 35fps. With 8 extra sprites are on screen, it averages at 24fps. With 12 extra sprites on screen, it averages at 18fps.

I intend to look at writing a faster sprite routine for enemies, bullets & animations that only handle clipping, but not masking. Those particular sprites don't really have any need for masking, and a routine that ignores masking should (in theory) operate at about twice the speed. Hopefully this allows me to release the throttle a bit and increase the frame rate without the game speeding up & slowing down too much when it has more sprites to draw.
EDIT: Based on the above tests, the game can run 20% faster when there are no sprites on screen. I'll be trying unmasked sprites to see if this decreases the speed reduction factor when there are many sprites on screen at once.

Hey, James, I think that your ABIV game was awesome!  One idea though: can the sprite for the main character be changed?  I gave the program to some of the kids at school, and, no offense, but for the longest time, they thought the avatar was a giant butt.    I am not joking.  I think that the Omnimaga community should try to create a better sprite...  

Haha, I've never heard it referred to as a giant butt before, but I can definitely see it I've tried to keep the sprite as close a match as possible to the sprite in the original Amiga games. However, I'm always happy to consider anything that gets drawn up. I would like to keep it fairly faithful to the original though if possible

Good idea guys, I've added "move level data into appvars for flash app build" to my to-do list

If anyone is willing to come to Australia for a meet up, I'm sure tr1p1ea and I would both be there