[layzee]

It's been a long time since I played the game but regarding the egg cover art, it probably has to do with the "time egg" (Japanese: 時の卵), a story-related item in the game.

Now that you mention eggs, it brings to mind Hanjuku Hero, a long-running series (main character is an egg man) of Japanese-only Squaresoft RPG/Strategy games starting on the Nintendo Famicom.

So maybe they do have a quirky interest in eggs down there at Squaresoft HQ.

Edit: Or check the link to Procyon above.