Photopia is really more of a story than a game. It's interesting and it's compelling, but if you're looking for traditional IF gameplay, this might not be your cup of tea. There are no puzzles and not even many choices to be made. But when it all comes together, it works like a well-written short story. And you're gonna have an emotional reaction that you might not have expected.
Photopia definitely pushes the boundary of story-telling in a way that few could have predicted when Interactive Fiction was first introduced. In fact, I would say Photopia is best viewed as an experimental work whose impact is found in later works of IF by Cadre and others.
It's a short, clever game. Somewhat of a one-trick pony, but still fun. Can be completed in 10 minutes or less. Not a lot of puzzles or really interaction, but still kind of intriguing.
This is a great, short piece of mystery. It's the classic "locked house, dead body, 5 suspects" genre of murder mystery done in an infocom style --complete with Sgt Duffy.
For me, just coming back to the genre after many years, this was a great intro. It's got a simple map with around 10 location, not too many objects, some modest red herrings and a good *logical* story.
Not to mention that, if you do get stuck, there are built-in clues. All this makes for a good easy game for newcomers also.
The actual who/how/motives are randomized, so there's some replay value, though some of the fun is really in the first time.