I just finished the second (?) mission of Anthelion (and that was the end of the demo!).
I am extremely impressed with the game. Kinda like Wing Commander for PPC. (Someone else mentioned Freespace, but I've only played WC3--which i loved btw, except that i could not for the life of me beat it.)
At first the game made me want to play a space shooter on my PC more than anything; i didn't have a lot of confidence in playing this kind of game on a 3.5" screen.
Most of my qualms with the game had to do with the controls. The d-pad as we all know isn't so hot, but even with "roll" deselected in the controls menu, the right and left controls tend to cause the ship to roll just slightly. The stylus control (implemented on the info part of the cockpit screen) seemed nauseatingly sensitive at first, but then i tried leaving the stylus on the screen continuously and it is now by far my preferred method of control. Previously i had been kind of swiping/tapping intermittently at the screen and that was producing rather awkward movement. (I mainly "swipe" now only when i need to make a big turn.)
the graphics are honestly very close to Wing Commander 3. A little grainier, perhaps, but still impressive and the game overall looks terrific.
As for performance on my Axim X5 Advanced, flight and combat was all perfectly smooth. CPU was set to auto. The most intense level was the second mission which featured a capital ship and 6 other fighters in addition to your own at its most demanding point. (the mission ran fine.) everything except dynamic lighting enabled. I don't even have a lot of free RAM--about 22MB total--and it still ran well. The demo is installed to my CF card.
As for plot, I can't say much because i only played a couple of missions. It seems the story mainly plays out via email transmissions (which even include spam! dont worry though, its pretty funny spam) and in-flight chat transmissions from other ships.
Important: If you choose to play a campaign on a specific difficulty level, you cannot reduce the difficulty level on a particular mission below your initial selection. It might thus be most sensible to choose Easy and then raise the difficulty of each mission to Normal or Hard; this way if you are stuck on a mission, you will be able to play it on easy without having to restart the whole campaign.
normally i wouldn't dream of spending $20 on a PPC game as i'm not much of a PPC gamer, but I really don't think i can hold out on this one. i'm just gonna play a little more to see if i'm really proficient at this PPC dogfighting stuff.
Just for the record, this was my 800th post. :)