🧵 Following Kosmic's recent discovery of getting past the kill screen in original DK Arcade ( www.youtube.com/watch?v=CoTQ... ), I took a look into how DK64's version of DK Arcade operates with the ladders, and it's surprisingly very robust! [1/7] - ThreadSky

ballaam.dk64randomizer.com • 25 days ago

🧵 Following Kosmic's recent discovery of getting past the kill screen in original DK Arcade ( https://www.youtube.com/watch?v=CoTQ53iM8c0 ), I took a look into how DK64's version of DK Arcade operates with the ladders, and it's surprisingly very robust! [1/7]

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ballaam.dk64randomizer.com•25 days ago

Let's talk the kill screen first: DK64's DK Arcade doesn't have one. DK64 caps the level counter at 9. Upon beating level 9, it'll start you back at the start of level 9. This might have been a protective measure against getting a kill screen in the DK64 port, but they didn't need it... [2/7]

ballaam.dk64randomizer.com•25 days ago

As Kosmic outlines, the pre-cap calculation of original Donkey Kong is an 8-bit number, which is where the overflow strikes. However, DK64 isn't bound by such limitations and is instead 32 bit, even if you somehow get past level 9. Additionally, DK64's bonus timer caps at 9k rather than 8k [3/7]

ballaam.dk64randomizer.com•25 days ago

In the original DK/NES remake, you could exceed the bounds of the level to wrap around to the top due to the Y value being an 8-bit value. In DK64, the Y value of sprites is stored as a 32-bit floating point number. Additionally, the game places a cap on the Y value to prevent funny business. [4/7]

ballaam.dk64randomizer.com•25 days ago

Additionally, the ladders in DK64 are incredibly rigid. If you exceed the bounds slightly in the y direction, you will be slowly returned back to normal bounds by the game. If you massively exceed them, then the game warps you below the level and you are softlocked. [5/7]

ballaam.dk64randomizer.com•25 days ago

What about the X direction? Whilst the ladder top/bottom detection would fail here, the developers were smart enough and exceeding standard bounds for the ladder in the x direction also warps you to below the level.
[6/7]

ballaam.dk64randomizer.com•25 days ago

In short, the usage of 32 bit numbers fixes a lot of the bugs with DK arcade. Some surprisingly robust programming (by the standards of 1999) also means that other exploits using ladders brings you to a softlocked state. [7/7]

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