Hello.

Size. The game field is currently 840x484. Background objects can be smaller. They can be larger if we are talking about movement animations. Then only part of the huge space object in the background will be visible.

Format - png. It will either be one static image. Or a spritesheet with animation frames.

The game is currently planned to have 25 levels. I would like to have different backgrounds at different levels. But this is too much work for an indie solo developer. Therefore, I use as many backgrounds in the game as you give me.

Details:

1. Definitely, the backgrounds should be single-bit. That is, either color or no color. Please watch the gameplay video or run the demo. See? Dark blue space and slightly lighter planets, a space station, and so on.
2. Definitely, the backgrounds should be space-themed. Even if some object is not directly related to space, it should be stylized as such. For example, if we want to make an ancient Greek temple with columns and statues of gods, it should be on a platform with engines, under an atmospheric dome and with antennas. Or something like that.
3. It is best to make small background objects with minimal animations. Size 128x128 or 256x256. And about 8 frames. I came to this during the development process. It is easiest to procedurally generate backgrounds for levels from such objects.

What do you say? Are you still interested?