Prior to the launch of the Dreamcast, a special Godzilla edition VMU, preloaded with a virtual pet game, was released on July 30, 1998, in Japan.

[1] While its most basic function is as a removable storage device, the VMU may also serve as an auxiliary display during normal gameplay and, through the use of additional software (distributed as extras on Dreamcast GD-ROMs), acts as a handheld game console.

Upon initial use, the player is prompted to set the date and time, and then select from a group of bitmap images to serve as the default background for the VMU (various Dreamcast titles may offer players additional background images for the unit).

Without battery power, the VMU still functions as a memory card and auxiliary display, but cannot play downloaded mini-games.

However, a handful of games might be unable to detect the memory card if this is done, although none have been reported apart from DreamKey/DreamPassport and Metropolis Street Racer.

In other video games, statistics such as the current health condition are displayed on the VMU for convenience (as in Resident Evil: Code Veronica) or to enhance multi-player gaming (for example, NFL 2K2 allowed the VMU to display secret plays not viewable to other players).

Sega released an official 4x Memory Card which offered four times the data storage of a standard VMU, with 800 blocks.

[6] The Nexus Memory Card is slightly larger than the normal VMU and can be connected to a personal computer by USB, Parallel or Serial cable.

In September 2023, following a successful crowdfunding campaign, Dreamware Enterprises released an aftermarket VMU update called the VM2.

They offered praise for the originality of the device, as well its flexibility and commented that newer systems should have revisited the concept.