About to crossover to mbile development, one little question

What sort of limitations, generally, are there on mobile devices that you don't have on PC? I've always designed for PC, and not sure what sort of changes in thinking I need to make to move into mobile development.

 

CPU, GPU, Fillrate, RAM, VRAM, Maximum Filesize if you don't create a proxy that acts as downloader (android marketplace has a 50mb filesize limit) and in case of Android performance difference in the range of a factor of 20-30 between the top and bottomst end device and very inconsistent quality on the graphics drivers and their bugs which normally means 'you develop for one or a handfull of devices where you can test it on and 'hope' for the rest)

 

So, not a bad idea to target the high end devices in design, as, over course of development, high end now will probably be middle to low end in about a year?