So I was thinking about Bubble Bobble again, and I was watching some of Summoning Salt's speedrun history videos, and I guess this is the result?

Bubble Bobble is one of the first games I ever played; a single screen platformer where you blow bubbles and eat fruit and sweets and powerups and try and make your way through 100 levels. It's a game that's always stuck with me for one specific reason, and that's the fact that it has no random number generator.

On the surface, this seems like an insignificant detail; the game's levels and enemies are hand-designed and don't change between playthroughs. If you pay attention to the game however, you might start to notice that the fruit and sweets and powerups that appear throughout the game are different each time, and seemingly chosen at random.

But if there's no random number generator, how is that possible?

It turns out that all this seeming randomness is actually purely deterministic; the game chooses which items to place based on the player's score and things like how many bubbles they've popped on the current level. Which means that high level play requires careful manipulation of your score and your play in order to trigger the best items (see here for a detailed breakdown of all these mechanics).

And of course, this process is not that different to a lot of speedrunning strategies, where you're often trying to manipulate the game to put it into a state that lets you race through it faster than the developers intended.

Anyway, that's a long preamble, but weird fruits is a game where item placement is determined entirely by your score. So in order to get the best items you need to manipulate your score carefully.

I also added a hidden speedrun timer which tracks how long it takes you to hit 1 million points after booting up the game. The game always starts at 0 points when you boot it up, which means it will take you a few runs before you hit a starting seed where 1 million points is even possible. Theoretically, because the game is entirely deterministic, it should be possible to calculate the single fastest route to 1 million points. In practice though, I find that impossible, as there are just too many numbers involved.

Does that make any sense? I feel like this is the most involved explanation of a here and then gone project to date, and I'm still not sure it's at all clear how the game works, and why.

Download weird fruits

Controls: escape: quit; cursor keys: choose destination tile; space: move to destination

The Rules:

The file at this link will be deleted 1 month from now (06/03/21).
All downloads are zipfiles containing a Windows executable.
All source code and assets are included, licensed under the GPL (code) and CC-BYSA (assets).
As long as you abide by those licenses, you can do whatever you want with the download.

Feb. 6, 2021, 10 a.m.

weird fruits

The Rules:

Further Reading