New features include PSG sound emulation and joystick support (although at the moment only linux svgalib has actually been modified to do this), plus of course lots of other emulation improvements.
I just tried this emulator after a long time of not using any (the last Genesis emulator I ran was kgen98 under DOS...)
Anyway, how about using any 320x240 modes which are available? That would have to be faster than doubling pixels.
I'm also getting a sound problem in Battle Mania 2, and the emulator under Linux seems rather slow... I have a Thunderbird 850 and can't get 60 frames per second with vsync on.... (It will do 60 fps with vsync in dos).
Generator could probably do with using the smaller resolution modes but then a new user-interface would need to be written. I'm not sure if the effort of doing that is worth it. Perhaps I could make it slaved from the 640x480 version so that you exit back into 640x480 to change options etc. Mmm.
I'm interested to hear that you have better performance under DOS than linux. What is the speed difference? What svgalib driver are you using? Have you tried the BIOS driver, or if you're using that, is there a driver for your particular video card?
Quite a number of people have said that their card has poor performance with either the BIOS or the one for their particular card, and switching between them has solved some slowdown.
On Linux using the Vesa driver it is around 54-60 fps with vsync and an analog joystick. It is around 58-60 with a Sidewinder. Using no joystick at all was slightly better than the Sidewinder, but not always 60 (and it still produces noticeable screen tearing).
Without vsync, it's 60 fps, and it's always 60 under DOS.
I thought I had tried the card-specific driver but I can't find it to try it again; maybe I deleted the line from my libvga.config by mistake. I don't remember any noticeable difference.
I am using the slower tilemap mode. Battle Mania 2 doesn't work using the faster mode.
Also, is there any way to do fullscreen without scanlines?