Thank you all for your comments!
Harty123 wrote:Please add a wiki entry for this game under Work-in-progress...
Will do!
martinsustek wrote:I have some tips to make it better:
A lot of the things you mentioned are part of the plan already: weapons, power ups, difficulty levels. I'll have to see how this all goes before doing much more as I already have a pretty tight flash budget.
D3thAdd3r wrote:I'd love to know some technical details unless you want to be secretive at this point

I imagine projectiles are done with tiles, what kind of level format do you use?
Nah, I like discussing that stuff, although at this stage it's all subject to change

The ship and the player's projectiles are sprites right now, but this might change depending on how the weapons work out. Everything else is tiles, so for collision detection I only need to check sprites against tiles, for which I use a map to get down to quarter-tile (i.e. 4x4 pixel) resolution.
The level format is based on a "stream" of columns which is rather crudely compressed by encoding runs of the same tile and occurrences of identical columns. This could be done a lot better, but it's simple and seems to do a good job of the relatively sparse maps I'm using (around 10% compression ratio). It helps that the stars in the background are superimposed randomly over what would otherwise be blank tiles.