Flashback was (and still is) one of the greatest games I have ever played. The game was created in such a way as to mimic the methods of storytelling and exposition used in feature films, which was virtually unheard of at the time. Games before were essentially "Here is your foe, go kill it." In fact, a lot of games are still made this way, much to my dismay. Anyway, in Flashback, your own identity, much less your opponent's, is unknown at the start and must be discovered through the process of playing the game.
The music is minimal, but still excellent; each piece of music is used to set the tone of what you are doing and of what is about to happen, also much like the score of a movie. The difference between the two is that in films, the score is often omnipresent, if subdued at times, while the game's music is short and 'to-the-point' in the mood it sets.
Controls and gameplay are similar enough to Prince of Persia titles (and to Delphine's previous title, Out Of This World), but have a fair bit more flexibility in what you are capable of (and what you can survive) by the inclusion of your items. Once you gain the personal force field, a highly skilled player may
be able to progress for most of the rest of the game without risk of damage, but those without godlike keyboard and gamepad reflexes will still be able to survive without going utterly insane.
The game includes some simple and some more complex puzzle elements, as well as requiring you to actually interact with the people of the world around you. The people are not just there for decoration or to complete an atmosphere; they will help you and betray you and tell you more about the world you occupy.
I've left the graphics for last, for obvious reasons. This was cutting edge. The use of cinematic-style cut scenes in this game only heightened the sense that you were a part of the game, a part of the action, and in many ways began the idea (in my own mind, anyway) that video games had the potential towards being an art form. The character designs are mediocre compared to the capabilities of today, but at the time the game was released were among the pinnacle of what you could find on the market. Each sprite moves as you would expect a human (or suitably-shaped humanoid) to move, and reacts to damage in realistic ways. Knock a guy over a cliff, and he will fall. If you run and jump to grab an overhang, you will sway until your momentum stops. Everything was done with great attentiveness to detail, which further enhances the realism that draws you in.
I haven't mentioned the story at all, you may have noticed, because I don't like spoilers, and this game is so much worth the play through on its own to find out the story. Go get it.