2D and The Illusion of Depth (Wario Land 4)

March 17th, 2011

One of Wario Land 4‘s neat graphical flourishes is parallax scrolling. Parallax scrolling is the technical term for layers of graphics that scroll independently from each other. Take the screenshot below and note the different layers.

Now take a look at the video below. You’ll notice that as Wario moves, the background layers move at different speeds.

This creates the impression that some layers are closer to the foreground than others, as elements that are further away move slower than elements that are closer. Actually though, Wario Land 4 is a 2D game. There is no Z-axis, only a set number of layers which create the impression of actual depth. Three or four layers of 2D sprites don’t equate to another axis, but they can certainly make the game appear more visually interesting.

The nature of 2D side-scrolling where one dimension is hidden from the player allows us to justify and rationalise abnormalities. After all, what is it that is keeping all those platforms suspended in air? Well, we don’t really know. It must be something behind the platforms that is obscured from our view. The very limitations of 2D make such assumptions seem more justified. Therefore, 2D we don’t often question the nonsense of 2D platformers.

I want to mention examples of these anomalies which we rationalise:

Suspension in mid-air

I talked about this one before. Platforms, blocks, crystals and other level elements can remain suspended in mid-air without any visible supports. Also, weak platforms, like the example below, that stay upright even though it doesn’t make physical sense for them to.

Enemies walking behind each other

Enemies in Wario Land 4 rarely influence each other by themselves. If an enemy walks into the path of another enemy they will just somehow walk behind them. This assumes that the 2 enemies have been walking on different layers. Even though one enemy is behind the other Wario can still smash attack the enemies and defeat both of them in one go. So Wario must be wide enough to squash the 2 enemies that are, from Wario facing out, side-by-side. In itself, this isn’t too difficult to believe. Wario is quite bulky, so he is probably as wide as the width of 2 common enemies. The logic begins to fail when you can knock as many enemies available into a small space and have many enemies standing behind each other.