There may be the odd issue with it but most things should work fairly well.
Let me know which version of Combat you used. Check in your log file which is created on the SD card.
Also, if you experience an error, please copy and paste the relevant lines from the log created on the SD card.
The entire log entry for the ROM would be most helpful.
Using the non-PAL version of Combat, I can see a bigger portion of the screen, but still it's not the entire screen space (I've tried the same roms in javatari emulator and I get the whole screen). Anyway you can find vAtari log file here:http://pastebin.com/17GwDCeL
But the worst thing now is that I've having a lot of issues with other emulators / applications! Some emus freeze the Dingoo (Proosystem, Gnuboy, SameGoo), others like MAME v1.3 and Temper just don't start anymore, others display the message "Simulator not exit, download please!" (SmsGGoo). Only default Dingoo emu seem to work!
I can't access some folders and files in the GAME folder of the Dingoo using Windows7, I think they're damaged.
When I have some time I will check if I can fix this mess