Recently I bought a "Castlevania" for NES. Since I bought it from Ebay, I decided to get NTSC version (mostly because of lower shipping costs). My console supports PAL format, yet after few "adjustments" it can run NTSC games as well. And here's my problem:
Game arived, but I noticed animation errors. During atacks, character "blinks" (disapears and apears).
Yet this is not major problem. Major problem is status bar (whole stuff that is on the top of screen: health bar, used item, points etc.). When I move forward and screen "scrolls" to another location, bar stays at its place. So, after beginning of level, if I proceed, I leave whole "status" behind. It's not like I can't play because of it, but it's rather annoying.
Here's the question: is there something wrong with cartridge, or is it natural outcome of using NTSC games on PAL console? Even though it's modified to run both formats.
I had also problem with Castlevania 2 (UK version) - when I wanted to type password, I realised that instead of letters and numbers, I have just some of the letters and symbols (hearts, etc) instead of missing letters.
I have no idea what caused this. It's kinda hard to believe that both cartridges are faulty.
Have someone encountered similliar problem, or have any idea what's going on?

Thanks for info. Looks like I'll have to get myself another console then.