In your pest busters game, why do the ships look like they're flying forward?
a.
the background layers don't move at all.
b.
the background layers scroll behind them.
c.
the visible play area is very wide.
d.
they are being shot from an object across the play area.

B.The background layers scroll behind them.

In most 2D games, the scrolling of the background is a common practice. The background layers are used to give the sense of motion to the player. The addition of a flying effect would give the player a better sense of motion and direction at the same time.

This practice of scrolling a background in games has been used due to the amount of space that the designers had to keep the focus on the characters of the game. A scrolling background also helps with the memory needed to general the different levels of a game. The scrolling background allows developers to simply generate areas and remove the unneeded areas after it has been used.

plot immersion i am not fully sure with it though