Back in 2003, developer Quantized Bit showed off Overstorm, an action platformer for the Game Boy Advance at a gaming convention. The title would not be seen again for more than a decade, as it was ultimately cancelled.
However, the developer — which is still going strong and creating indie titles — is giving away an alpha version of Overstorm with Indiestand title Volt — its most recent release — which is available on PC, Mac, Linux, Android and iOS.
Unseen 64 has picked up on this event and has posted screens and assets from the title, which looks incredibly polished and detailed for a GBA release. You'll need a GBA emulator to play the game — it's supplied in ROM form — and it's naturally far from a finished project, but nevertheless remains a neat extra if you're a Nintendo historian.