Star Wars: X-Wing vs. TIE Fighter marked the first time the venerable Z-95 Headhunter had shown up as a playable craft in a X-Wing series game. While it had previously appeared as an enemy fighter in both X-Wing and TIE Fighter, its playable inclusion in XWvT was definitely something fans had been waiting on for a while.
In XWvT, the Headhunter sits somewhere below the X-Wing in terms of capability. It shares the X-Wing's speed, but carries only half the armament, and much lighter shields. Fitting, in lore terms, since the Z-95 is generally written of as being the X-Wing's design predecessor.
However, unlike the iconic X-Wing, which has changed very little in terms of design and description of the history of Star Wars, the Z-95 has undergone numerous radical changes, with wing type and the number of engines being the most obvious.
The first in-universe description of the Headhunter came from Han Solo at Star's End, the first book in the Han Solo trilogy, released in 1979. The Z-95 at the time featured variable geometry (swing) wings, and multiple blaster cannons.
In later books, the Headhunter lost the swing wings and took on the proto X-Wing style with four engines, a single pair of straight wings, and wing-tip mounted lasers. This is the style that appears in the X-Wing series games.
With the Clone Wars TV show, however, we got a new version of the Z-95. Used by the Clone troops, this variant drops the quad engines in favor of a more streamlined engine pair. With the Legends/Canon split by Disney, this has become the only seen variant, although the new comics have been busily adding the old four-engine style back into canon.
Any way you look at it, it's a fun ship. And while my time with it in-game has likely passed, having moved to more difficult missions featuring classic Rebel alphabet fighters, seeing the new incarnations really makes me wish for a new X-Wing series game in the Clone Wars timeline!
Z-95 Headhunter lore from Wookiepedia. Watch my continuing Star Wars: X-Wing vs. TIE Fighter - Balance of Power campaigns on Twitch and catch the archives on Youtube.