I don't know what you mean by "it's a cross section of the high...

I don't know what you mean by "it's a cross section of the high case scenario". This is seismic DATA. The high case scenario is an interpretation taking into account various risks/sizes etc.
The increased amplitudes you are seeing indicate a greater impedance contrast between those rocks and the ones above it. Basically big changes in the seismic wave velocities. You expect a significant change to wave velocities when you go from a shale to a sandstone for example, because the poroelastic properties are very different (Young's modulus, Poisson's ratio, shear modulus etc.). But the key here is when you replace water with gas for example, you may even enhance this difference more which is manifested by higher amplitudes. NOTE: there are things other than gas that could cause these amplitude increases. For example if there was a pocket of overpressured water in there, the effective pressure would be reduced and the velocities would decrease.
As for being continuous..looks pretty continuous to me...whatever it is. :)