The challenge was to capture my knowledge into a computer program.

December 10, 2018 10:42 AM

CastlevaniaBot is a plugin for the Nintaco NES emulator that plays Castlevania. It "is a system that simulates the same decision-making process that I perform when I have a controller in hand. Creating it involved articulating in elaborate detail the physics that govern Simon Belmont’s 8‑bit world and all the tactics required to be an expert vampire killer."
posted by a snickering nuthatch (7 comments total)

This is a tangent, but I find it really fascinating that almost nothing is known about the lead programmer and designer of Castlevania I, II and III except his name, Hitoshi Akamatsu. It's one of the most important and influential games in history, and no one seems to know where he is, even old employees of Konami.
posted by Kattullus at 12:14 PM on December 10, 2018 [12 favorites]

I love this. The idea of modeling simulated behavior on practical human heuristics has always been interesting to me, for the way that it (a) requires an examination and enumeration of what those heuristics are which can be really fascinating in its own right, and (b) produces automated behavior that, while probably not optimal, can be really relatable. I did some work a while back trying to work out nonogram solving as a set of discrete mental moves of the sort that I make myself when solving them, partly because I liked the idea of being able to watch a computer actually work through a puzzle the same way I would; this is making me want to get back to that.

Anyway:

Just prior to collecting the crystal ball, CastlevaniaBot tosses it’s subweapon around, knowing that it will freeze midair as soon as the crystal ball is touched. Then, it repeatedly jumps and whips randomly, hoping to get frozen in a strange pose.

I was enjoying reading through this already but that's the moment where I burst out laughing. This is perfect.
posted by cortex at 12:34 PM on December 10, 2018 [8 favorites]

Don't forget The Goonies 2, Kattullus.
posted by sysinfo at 1:52 PM on December 10, 2018 [3 favorites]

Oh wow! It's amazing to see photos of Akamatsu, sysinfo.
posted by Kattullus at 2:07 PM on December 10, 2018 [1 favorite]

all the tactics required to be an expert vampire killer

AI is going to take all the good jobs, isn't it?
posted by asperity at 2:50 PM on December 10, 2018 [4 favorites]

Great read, thanks for posting this!
posted by longtime_lurker at 8:50 PM on December 10, 2018

I liked this part: the underlying realization that perfection is perfectly boring and that deliberately introducing jitter leads to more interesting variation.

No matter how skilled they are, humans cannot fully tame the RNG; however, since CastlevaniaBot can control button presses at frame granularity, it could take that speedrunning concept to the extreme by playing exactly the same game during each run. If it did, it would hardly be better than a TAS recording. Instead, CastlevaniaBot deliberately introduces minute errors and delays into its actions using its own external RNG to avoid deterministic gameplay. For instance, when it whips a high candle it intentionally delays the jump and the whip strike by a few random frames. Tiny changes like that have a significantly effect on how the game plays out.

posted by We had a deal, Kyle at 7:06 PM on December 11, 2018 [3 favorites]