I've just started running GNU Freedink in what appears to be a framebuffer. I'm not experienced with such things so I don't know, but it is running as invoked from a virtual terminal and without X running to handle the graphics, which I've been told means framebuffer.
I've been experiencing a flicker in the graphics near the upper area of the screen. About a quarter of the screen all the way across is affected starting at about a sixth of the way down. If I recall correctly it seems to affect sprites and not the background. The flicker renders the sprites almost constantly invisible.
I've not yet gathered any more info on this bug but would like to see if anyone knows about it. Freedink 0.8 is what I'm running -- so its not absolutely recent -- installed from the Debian repos on an armv6l machine. A Raspberry Pi to be specific. I did not experience this bug while running Freedink with X to display.