Download is a horizontal shoot 'em up set in a dystopian cyberpunk future in which the main character, Syd, is haunted by memories of his friend Ohala falling to a cybernetic menace. Meanwhile, he receives a call from his contact/partner Deva and must rush to her rescue when she is abducted by the Kabukicho police force. The game's story is depicted in a series of animated vignettes before each stage, similar to Ninja Gaiden. Beginning with the mean streets of Kabukicho, Syd eventually jacks into the internet and fights in a similar manner through cyberspace.
Download is perhaps best known for its profanity-laden game over messages. It was followed by a PC Engine CD sequel the following year: Download 2.
Syd's hoverbike has variable loadouts that the player can assign at the start of each level. These weapons can be upgraded further by finding power-ups within the level. The chief weapons, which can be fired infinitely, include a focused laser weapon and a scattered beam shot: the former is best for bosses and stronger foes, while the latter can quickly eliminate large crowds of weaker enemies. The player will often need to play each level a few times to determine the best loadout.
The player can also select between three sub-weapons: chaser missiles, which home in on foes; crusher, which absorbs shots and causes explosions; and barrier, which stops shots for a short time. Each sub-weapon has a finite number of uses which can be replenished by finding the right power-ups.