Zool: Taking It to the N Dimension - The Game Maker's Companion: Game Development - page 51

Figure 3-2. One of the original sprite sheets from the Mega Drive version of the game. It is interesting to see
how they were laid out in a 48x48 grid against a single color background (lines added)
Kitchen Tiles
You are probably quite used to thinking about your levels being divided into a grid of equal-sized
squares, as this is the way that Game Maker usually works. The original Zool game also divided
the landscape into squares. These were only 16x16 pixels so that a relatively small number of tiles
could be rearranged in different combinations to produce a wide variety of levels. In Zool's era, it
was extremely common to construct levels out of very small tiles in this way because of the
limited memory available on the hardware platforms. Figure 3-3 shows tiles from the Sweet
World, which was the first enemy world encountered in the game and the one we'll be using in
this topic.
Game Maker supports tile sets , as a way of representing a level in a similar way. You may have
used them before, perhaps even in the Koalabr8 game in The Game Maker's Apprentice. A tile set
is used to create the visible parts of the landscape, but tiles are non-interactive (they can't have
events and actions), so invisible objects are placed on top to handle any interactive behaviors. It
also means that any number of tiles can make use of an identical object behavior: providing
visual variety without adding hundreds of objects to your game.
Figure 3-3. Some of the 16x16 tiles originally taken from the SNES version of the game