ZellSF: Widescreen working perfectly even for FMVs (which the old widescreen would both letterbox and pillarbox) is nice, but it's also a bit inferior for two reasons. First there's no resolution choice (1024x600 seems to be the one you get, which is less than the 1280x720 I would prefer) and second there's no option for integer scaling (
http://tanalin.com/en/articles/lossless-scaling/ ) which could be forced on the existing game if you used DXGL or DxWnd.
robip85: Probably 1024x576 with 16:9 and 1024x640 with 16:10. But otherwise it takes desktop resolution and scales it.
Width is certainly 1024, as I compared it to original game.
It's fine to me as I like a normal size HUD.
Yes, I noticed when testing Robin Hood widescreen that 1024x600 isn't widescreen and realized that meant I was wrong about Desperados, but didn't feel it was important enough to edit my post.
I find 1024x576 to be very wrong, I used to play it at 1024x768 on a smaller monitor. Less resolution at a larger display size isn't a normal size HUD, or a normal size game. Everything is too large.