When you reach the second stage, in that specific area (the one shown in the photo), some vertical lines appear. They are very subtle, that is, they appear and disappear. I think they do that a couple of times:
The photo is the game in demo mode, but when you play it and you get to that area of the stage it does the same thing.
I don't know if it's an emulation error or if the game is like that, but I tried in mame and those vertical lines don't appear.
Greetings.
Edit: It only happens when you shoot lightning bolts into the steel columns of the stage, and they come together with the explosion of the helicopter. So it's not something that will always show up there.
Complete that stage without destroying the steel column or the helicopter and those vertical lines didn't show up. But when you destroy the columns in that area (seen in the photo) the lines will appear.
It's probably normal, but I don't know. I leave it to you who are the experts on this.
But it's strange, because in mame, when you destroy everything in that same area, those vertical lines don't appear... that's why I'm a little confused.
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Edit 2: Maybe I should have put this problem in the same thread I opened a few days ago since the game is the same (superman). I apologize.