Developed by Freestyle and originally published by U.S. Gold in 1995, Mega Man's sole Game Gear outing mashes together elements from Mega Man 4 and Mega Man 5, with uneven results. If nothing else, the eShop release will be significantly cheaper and easier to find than a cartridge copy, as original Game Gear Mega Man carts are currently selling for around $40 on eBay.
As of last week, all six NES Mega Man games are now available in the 3DS eShop. After the Game Gear version of Mega Man launches, Capcom may turn its attention to the remaining Game Boy entries in the series, following up on the 2011 Virtual Console release of Mega Man: Dr. Wily's Revenge. Here's hoping that we'll see a port of Mega Man: The Wily Wars at some point.