256 bytes

3Blue1Brown illustrates how enormous the 256-bit search space is, showing how infeasible it is to find a hash or key by guessing and checking.

Morphcat Games explains how they fit Micro Mages, a full-featured NES game, into 40 kilobytes. It covers compression of sprites and level layouts and other space-saving tricks.

Anders Brownworth gives a basic visual introduction to blockchain using an interactive web demo, covering SHA256 hashes, blocks, chains, distribution, tokens and coinbase transactions.

A recording of .the .product by Farbrausch, the first-place 64k intro at The Party 2000. It fits an 11-minute 3D demo with music into 64 kilobytes.

Chaos Theory is a 64k demoscene intro by Conspiracy and CNS that took second place at Assembly 2006, generating its graphics and music from a tiny executable.

A Samsung-backed viral demo that builds a fast computer from 24 256GB MLC SSDs in a RAID 0 array and shows the throughput results.

Gameplay footage of Zarch, the 1987 3D Defender-like game by David Braben for the Acorn Archimedes. It shows the 256-colour 3D landscape where you stop landers spreading a virus.

Onslaught's Bad Apple 64 is a Commodore 64 demo that streams over 2000 frames of the Bad Apple animation from a single disk side at 12fps, with each frame packed to around 70 bytes.