Well, impressions:
Syphon Filter plays like Syphon Filter. There's a touch of nostalgia, only with an additional hint of "man, Splinter Cell really changed this espionage game genre for the better, didn't it?" feelings.
Loads up and plays fine. Good load times.
The game looks like the PS1 version. No enhanced textures, no special bosses, not a damn thing changed. That's good, and no different from what the virtual console offers you.
Pressing "Home" mid-game brings up several options. You can reassign the controls (external to the in-game options), view the manual (which is a high-quality scan of the PS1 booklet), change the screen size ("original," or tiny, "normal," or larger but with the same aspect ratio, and "full screen," which you better be able to figure out for yourself. Full screen wasn't something I dug, I must admit.
In the Playstation Store, you have a tab called "download center" which lists everything you've downloaded thus far, including PSOne games and licenses. It looks like I'll be able to delete this game and download everything again if I need the room to do so.
As for copying it to another source (say, an HDD) and back, I don't know. I may try it tomorrow, but most likely not.
The license aspect seems interesting, and makes me wonder if its used to prevent piracy as well as allow you to copy it to an external center for later use. Keep the license on your memory card, delete or copy the game at will, and copy back over if necessary. My guess is that the license configures itself to give the game a key to only play on a PSP with the serial number, or some other unique identifier, that I have on my system.
So, keeping a 100KB file on your pro duo, while copying titles back and forth when you want them, that sounds like a helluva option. Perhaps I will try it tomorrow.
If Sony can create a PC program with the ability to sell licensed PSP software, and avoid the PS3 workaround (it sure seems like a workaround, and an inconvenient means of getting the PSOne titles), they'll do gangbusters business.
ATM, Tekken 2, Syphon Filter, Hot Shots Golf 2, Crash Bandicoot, and one other title (I forgot) are available.
Color me impressed.