Information in the game database is updated periodically. Below, you'll find that information compiled as pertains to ZyX. The company may be involved as a publisher, developer or both.
Amorous Professor Cherry (PC) [July 3, 2008]
Chain: The Lost Footprints (PC) [July 7, 2002]
Do You Like Horny Bunnies? (PC) 
Do You Like Horny Bunnies? 2 (PC) 
Lightning Warrior Raidy (PC) [April 8, 2008]
Ring Out (PC) 
The Sagara Family (PC) [January 27, 2005]
Tsuki ~Possession~ (PC) 
Virgin Roster ~Shukketsubo~ (PC) [December 19, 2003]
There are numerous companies in the industry, and their names change like the weather. The information above is not particular about the finer details. Acquisitions are common, so companies with no recent listings may still be developing games under a new name. For example, DMA Design currently has a Rockstar name. Do you know of a title that is not listed above but should be? Be sure and let a staff member know. You can contact staff if you click here.