Forgive me, this is the only game I wish to discuss...
Here we have the bland, sterile Japanese cover for my favorite underdog (perhaps, back in the day, this 3D CGI-inspired art invoked more passion from folks... but even when this art was cutting-edge, this composition would have been considered sterile and static):

I wouldn't mind this cover so much if it had a different composition. All of the exising elememnts could be arranged in a much more exciting manner. Oh well.
Behold! The glorious North American cover (honestly, this has a lot of things going for it):

I love the spirit of pinball and psychedelia this cover invokes. How about the trippy mobius-inspired green tube thing? When I see this cover, I want to ride a motorcycle through the GRAND CANYON. I want to listen to THE WHO at the local deli. I want to do it all. Thankfully, playing Timeball is as exhilerating as all of these activities. Let's go on a road trip, guys...
If only the artist for the TG-16 cover had taken inspiration from
this work of art!

Clearly, there is an inherent drama in Diablo's composition that you simply do not find with the U.S. version. The Japanese and U.S. artwork is too abstract when compared to Diablo. Despite this, the U.S. art still manages to invoke some
passion and exhileration -- no small feat.
Note: The artist of Diablo took liberties. He cheated to achieve the great drama in his art. On those grounds, the TG-16 artwork is the clear winner!
I suspect that the look of horror on some of your faces right now might match that of our friend above -- if so, then SHAME ON YOU. Diablo's cover is still brilliant, and thus a very strong runner-up.