It's not that I disagree with Roger Ebert's assertion that games will never be art; it's that I think he has such a good point, phrased in such an incendiary and definition-debating way, that oh God I'm already bored with this sentence I hate this discussion so fucking much. Anyway, Prince of Persia is a videogame in perfectly-adequate-movie form, and as such its biggest problem is that the central device - a dagger that can control the flow of time - is designed to be an ingenious toy that players can interact with, so when you take away the control pad, the result is a movie where you spend most of your time frustrated with the characters for not using the thing correctly.
Other than that, the dagger is adapted fairly faithfully from the game, in that it can turn back time and give you a one-minute do-over as long as you only ever use it for incidental things that have no effect on the actual plot. Just as the makers of Final Fantasy: The Spirits Within were savvy enough to include all sorts of wack-ass magical doodads but never let the characters use them in a way that could impact the actual happenings of the movie - just like in the games, wahey! - people in Prince of Persia never think to use the magic knife to prevent a beloved character's death, or prevent their own death, or not meet up with Alfred Molina's mortifying brownface comic-relief character.
One of the most charming things about the game version of The Sands of Time is its recurring use of the motif of storytelling as the power over time itself: the game's ludological employment of the chronotropic dagger is mirrored by frequent reminders that you're playing a story, and the storyteller himself can reverse time also. The movie admirably attempts to recreate this, but while some instances work, there's much clunky unintentional narrative time-bending going on too: at one point, the script jumps back to an earlier pivotal line to make sure we know what's going on, but that line was spoken less than a minute ago. Also, the entire plot is a heavy-handed attack on scheming politicians who would invade the Middle East in search of nonexistent contraband weaponry, because apparently the script thinks it is jumping back eight years to an era when this would be timely. I hope G. Gordon Liddy is sitting down, because the Prince of Persia: Warrior Within movie is really going to tear him a new one for that thing he did in the hotel that time, and not a moment too soon!
In conclusion, I cannot tell the difference between an actor who is having a ball re-enacting the glory days of matinee-idol bravado and an indie stalwart who is visibly embarrassed to be in a movie whose central theme is expressed as "the bond between brothers is the sword that defends a kingdom," so don't ask me whether Prince of Persia: The Sands of Time is any good, but it isn't.