Europe's Wii U Virtual Console games look likely to run at 50hz, significantly slower than their US and Japanese equivalents.
The first retro title released on the console, Balloon Fight, is confirmed to run at the 50hz frequency, as opposed to the 60hz versions available in other regions.
During the 80s and 90s 50hz was standard in PAL regions, with many ports suffering from large borders and 17 per cent slower gameplay (Sonic the Hedgehog was particularly bad).
Balloon Fight was Wii U's first Virtual Console release last week, and as you can see in the video below (thanks Nintendomination) there's a significant difference in speed between the US and EU/AUS versions.
Currently the Balloon Fight Miiverse is filled with messages criticising Nintendo's decision to release the 50hz version - and fans have even started a petition calling for the platform holder to release future Wii U Virtual Console games in Europe and Australia in 60Hz.
Balloon Fight is the first in a series of celebratory Famicom 30th anniversary releases on Wii U, with each costing £0.30 for their first 30 days of availability.
With the full Wii U Virtual Console service not due to launch until spring, the creators of the petition feel there may still be time for Nintendo to switch to 60hz releases, as it has done on 3DS.
CVG has contacted Nintendo UK for comment.