A brief John Carmack interview from Guardian Unlimited: Gamesblog

Was it strange returning to the very origins of Doom - in terms of graphics, CPU, memory restrictions? Did it bring back any memories of your work on the original game?I’m really not the reminiscing type. Capabilities wise, everything I was able to do back then, I can do a lot better now, but the mobile platform isn’t well suited to tight optimization because of the incredible range of performance you are expected to support. From our low-end Java platform (which is really a mid-range java platform, we don’t support the real low-end) to the high end BREW platform there is a performance difference of well over 20x.

I did take some value out of looking at the extreme simplicity of implementation that the tight resource limits required. I do feel that modern games are often abstracted a lot more than is really necessary, and it leads to robustness issues.