are there any name for shmups that has not level layout and are simply random enemy waves you shoot on one single screen?
you mean like Asteroids?
>>4058739
more like defender.
>>4058745
it's listed as a side-scrolling shooter, which probably isn't all that helpful
>>4058731
They're sometimes called fixed shooters, or gallery shooters. Defender is different though, kind of an oddball.
>>4058745
But that's not what defender is. It has a level layout, although it's not really relevant to game play and it obviously scrolls from side to side. Not quite sure what the question really is at that point.
>>4058745
I think defenders is a level layout, but because your movement is indepdent from forced-scrolling (like shmups) it may not seem that way.
I know what OP's trying to say though, I just can't think of anything like it
Not retro but Warning Forever.