resolution detection issue in v1.6, NTSC versions (U/J) only - black border at bottom. Can force resolution to fix but not recomended as game changes res.
Why does the game slow down in places?
Some parts of the game will have higher system requirements than others, for example larger levels, more enemies on screen - to some extent this is normal, the original system also tends to slow down in these situations, though it's not necessarily unpreventable on the emulator. Anything you do to improve performance generally will help (see User Manual). Some people (with very fast systems probably) find the game runs very smooth (smoother than real hardware) with Counter Factor changed from 2 to 1 (Advanced settings enabled, ROM Settings), try this if you like but be ready to put it back if it runs worse for you.
Why does the campsy, night vision etc not work?
Probably your graphics card does not support the necessary modes - these effects are supported on high end hardware. Also see known issues above.