Archive entry by Ste Pickford on Sun, 26 Nov 2006
In light of the very limited RAM space we had to work in on 8-bit home computers, it's interesting to compare the Spectrum and Amstrad versions of the same game, as the machines were pretty similar in internal architecture. The Spectrum had 48K RAM, but the screen (256 * 192 pixels, 1 bit per pixel) took around 6K or so, and with other bits of system stuff reserved there was around 40K free for the game to use. The Amstrad had a whopping 64K RAM, but the screen was a fair bit larger, and had 4 colour graphics, so the screen took up something like 16K (320 * 200 pixels, 2 bits per pixel), and with system stuff reserved there was probably only about 44K free.
That's still slightly more than the Spectrum, right? Wrong! All the in-game graphics took twice the RAM because 2 bits were required for every pixel, rather than 1 bit on the Spectrum. By doubling the size of all graphics, in more or less the same amount of free RAM, the Amstrad version of a Spectrum game (where the Spectrum was the lead version, as it usually was) always required some drastic cuts to fit in RAM. The perception was that the machines were more or less the same, or that the Amstrad was slightly better, so we had to try and make the cuts as close to invisible as possible.
We wanted to keep a unique baddie for each planet, and as we could change the colour palette for each planet we decided it would be fairly painless ditch the unique floor and platform graphics and just use the first planet's floor recoloured for the other nine planets. Nobody would notice, surely?
About half of the baddie sprites are re-coloured versions of the Spectrum ones, but the other half are unique to the Amstrad version. I can't imagine why I did this, especially as the new Amstrad ones look like Spectrum rejects. I've no idea what I was thinking with #9 - was he supposed to land on the floor and walk towards you? He looks like something out of the first issue of Viz comic.