You guess which one is Very High with high detail textures and which one is medium without high detail textures.

http://imgur.com/a/hNNfZ#1

if your graphics card doesnt support the features of the very high detail then they will look like the high

ATI Radeon HD 5450, more than enough for this game...

the graphical difference in a screenshot is not that much no. especialy in gal with little light effect like lyceum. There are 2 very big differences between medium and high (high and veryhigh on the other hand are pretty much identical except some effects flagged as very high only)

1. medium use pixel shader 2.0, high+ use pixel shader 3.0 hence the difference in light effects.

2. at medium, the rate at which some stuff update like particles, floaty image, target images, is a lot slower. Also ship model animation (not simple animations like the bulk rotation, those are done using another technic that isnt hard on the gpu so it didnt matter) but animations like basil, ds, some aibase are all disabled.

where as at high animations are all here, and everything update faster hence will be smoother on the eye. At very high those value are even higher.