Electron maintains an internal display address counter. The same counter is used in both the continuous and non-continuous graphics modes and switching modes mid-frame does not cause any adjustment to the counter. Firetrack switches from a non-continuous to a continuous graphics mode partway down the display. By using the palette to mask the top area of the display and taking care about when it changes mode it can shift the continuous graphics at the bottom of the display down in two pixel increments (rather than the usual eight for vertical scrolling) because the internal display counter is not incremented on blank scanlines during non-continuous graphics modes. Reception Zzap!64 gave an overall score of 88%, commenting that the game could "truly be said to be of arcade quality" and is "Fast, frenetic and extremely playable—easily the best vertically scrolling shoot 'em up to date". Electron User, when reviewing the Play It Again Sam 7 compilation, were also very enthusiastic with reviewer Martin Reed praising the "amazingly smooth vertical-scrolling" and stating "The graphics are stunning and give an amazingly realistic 3D effect that I wouldn't have thought was possible on the Electron". In her second opinion, Janice Murray claimed it would be worth buying the compilation even if you already owned the other three games: "This technically brilliant piece of programming makes a fine game which proves to be very fast and addictive. The other titles can be considered bonuses thrown in for free". References 1987 video games Aardvark Software games BBC Micro and Acorn Electron games Commodore 64 games Single-player video games Superior Software games Vertically scrolling shooters Video games developed in the United Kingdom