How would you structure this game?

Hi guys,
I wanna make a flash version of the 1989 Amiga game called Battle Squadron. It’s a game where you fly around in a spaceship, shooting down enemies, avoiding bullets, picking points and better shots etc.
You see the game from abone, and the screen is scrolling down to give the impression of your spaceship flying up.

My problem is that I cannot figure out what the best way to build the game level engine for this is.
I think it’s probably best to create a tile game, since there are a lot of repeating items in the ground, but the problem is that so many things are happening at the same time, that I’m afraid it might become way too slow to play.
Also, the best thing is probably to store the game levels in XML files, but I’m not shure how to load them in. I’ve used XML files before, which worked fine, but back then I loaded and built the whole level (in a platform game) at once, which resulted in way too many tiles having to be moved. What can I do to only load items before they appear on screen?

Oh yeah, one more thing (hang on, I’m almost done):
Do you guys have any suggestions for how to structure the XML files holding the levels? I don’t think the simple buildup of rows containing numbers relating to a specific movieclip will work - again because way too many things will need to be loaded in, and some items might need to be loaded on top of each others (i.e. some ground item + an enemy spaceship).

Btw, the game will be built with OOP AS 2.0…

Let’s get a discussion going :slight_smile:

Im doing a similar game (based on raiden) with much more remedial code… I’m hoping it works out for me…
good luck man…