Why Does Donkey Kong Have a Kill Screen?
The original Donkey Kong arcade game has a kill screen, specifically at level 117 (screen 116). This isn’t a deliberate programming choice to end the game in a dramatic fashion. Instead, it’s caused by an integer overflow error in the game’s level calculation. The number representing the current level exceeds the maximum value the game’s memory can hold for that specific variable, resulting in a value that effectively breaks the game logic and produces an unplayable screen.
Understanding the Donkey Kong Kill Screen
What is a Kill Screen?
A kill screen is a point in a video game where it becomes unplayable, usually due to a programming error or limitation. It’s not a designed ending but rather an unintended consequence of how the game was coded. In modern games, kill screens are rare due to more robust programming languages and larger memory capacities.
The Specifics of the Donkey Kong Overflow
In Donkey Kong, the level number is stored as a single byte. This means it can hold values from 0 to 255. However, the game calculates the amount of bonus time awarded at the start of each level based on the level number. Specifically, it uses this value to determine positions within a jump table, which is a list of memory addresses that the game uses to call specific routines. When the level reaches 117, the calculated value overflows beyond the boundaries of this jump table. This directs the game to execute code from an invalid memory location. This causes a series of bizarre graphical glitches, and importantly, the level layout is corrupted which makes the level virtually impossible to complete.
The Resulting Unplayability
This integer overflow corrupts the game’s data. The ladders often disappear or are placed in impossible locations, making it impossible for Mario (Jumpman) to climb to the top of the screen and rescue Pauline. It’s essentially a game-breaking bug triggered by the specific level number and the limitations of the game’s memory.
Frequently Asked Questions (FAQs) about the Donkey Kong Kill Screen
1. Is the Donkey Kong Kill Screen intentional?
No. The kill screen in Donkey Kong is a result of a programming error (specifically, an integer overflow) and not an intentional design feature.
2. What is an integer overflow?
An integer overflow occurs when a numerical value exceeds the maximum value that a variable can hold. In the case of Donkey Kong, the level number becomes too large for the allocated memory space, causing the value to “wrap around” and result in unexpected behavior.
3. Which version of Donkey Kong has the kill screen?
The kill screen exists in the original arcade version of Donkey Kong. Emulated or ported versions might have fixed the issue, depending on the specific implementation.
4. Can the kill screen be avoided?
In the original arcade version, no, the kill screen cannot be avoided. Reaching level 117 is a natural progression in the game. To avoid it you would have to stop playing before reaching that point.
5. Has anyone reached the kill screen legitimately?
Yes, many skilled Donkey Kong players have reached the kill screen legitimately. It requires a significant amount of practice and skill to progress that far in the game.
6. What happens exactly when the kill screen appears?
The game screen becomes corrupted with graphical glitches. The ladders are misaligned or missing, the level becomes unplayable, and the player is likely to lose a life quickly.
7. Is there a way to “fix” the kill screen in the original game?
No, there is no way to fix the kill screen in the original arcade machine without modifying the ROM (Read-Only Memory) chips that contain the game’s code. However, the source code can be updated in emulators to avoid the error.
8. Why didn’t the developers prevent the overflow?
Back in the early 1980s, when Donkey Kong was developed, memory was extremely limited and expensive. Developers often had to make compromises in code optimization, which could lead to issues like integer overflows. Preventing the overflow would likely require more memory space, which they could not afford.
9. Does this type of error happen in other classic games?
Yes, many other classic arcade games and early console games suffer from similar limitations and bugs, leading to kill screens or other unexpected behavior. Limited processing power and memory were common constraints.
10. How did players discover the Donkey Kong kill screen?
Players discovered the kill screen through regular gameplay as they got better at the game. As they progressed further and further, they eventually encountered the glitch at level 117.
11. Is the Donkey Kong kill screen famous or well-known?
Yes, the Donkey Kong kill screen is relatively famous within the gaming community, especially among retro gaming enthusiasts. It has been documented in documentaries like The King of Kong which follows players trying to break the world record.
12. How does the kill screen affect world record attempts?
The Donkey Kong kill screen represents a natural limit on the maximum possible score. Players trying to break world records have to reach level 117 and obtain the highest possible score before the game becomes unplayable.
13. Are there any other interesting facts about Donkey Kong’s programming?
Yes, Donkey Kong’s programming contains many other interesting details and quirks due to the constraints of the hardware. The way the game handles graphics, enemy behavior, and scoring is all highly optimized and fascinating to study.
14. Are there any games that have intentional kill screens?
While rare, some games might include intentionally designed kill screens as a form of a very difficult challenge or an unconventional ending. However, these are usually distinct from the unintentional, glitch-based kill screens like the one in Donkey Kong.
15. Has Nintendo ever addressed the Donkey Kong kill screen in official re-releases?
In some re-releases of Donkey Kong, Nintendo has addressed the kill screen by patching the ROM to prevent the integer overflow and allow the game to continue beyond level 117. However, some purists prefer to play the original arcade ROM, complete with its limitations and quirks.