It’s not for want of trying, that’s for sure.
There have been three (well, maybe five, but we’ll get to that later) games developed based on the property over the years, one in each of the past three decades. All are based on the more abbreviated version of the storyline (as well as the imagery) found in the 1988 anime adaptation of the classic manga series.
Aside from the three games that did surface, there were two versions of the game that, while publicly announced, never made it to a retail shelf. One of these was a console game to be released on the SNES, Genesis and Sega CD, while the other was a handheld title destined for the Game Boy and Game Gear. THQ was originally planning to publish both games.
While the handheld title was a simple arcade title split between bike and on-foot sections, the console game was incredibly ambitious, which may explain why it was never actually released. Akira on the Genesis and SNES was like a buffet, each level utilising a different genre to tell a different part of the film’s story. So the player would go from first-person exploration to side-scrolling shooting to isometric adventuring, each stage offering different challenges and a different way to play the game.
It’s certainly a unique approach that some other adaptations of the time tried (albeit to a lesser extent, like Jurassic Park’s blend of first-person shooting and third-person adventure), and one that may have been utilised to get around the fact the comic/film was actually a tricky property to turn into a game, given that it’s split so clearly into fast, action-packed sequences and long, slow periods of exposition.
Only the console game was ever playable (the Genesis version at a couple of trade shows in 1994), and despite both versions having been worked on in the West, playable builds have never been released to the public, even after all these years.
For more information on the unreleased games, you should check out this great Hardcore Gaming piece on them, which includes a ton of scans from the gaming magazines of the time.