GLORIOUSLY BAD! 
If Dirge of Cerberus, the PS2 game, is gloriously mediocre as a whole, this mobile phone chapter is gloriously bad. It has that sort of "Superman 64"-bad feel to it. The annoying sound of Vincent's shoes gives you a headache in a way that's actually fascinating. They were able to squeeze in voice files with good quality, but they couldn't get Vincent's shoes right to be easy on the ear? Could be that the method of recording (it appears to be a very well-done filming of the phone) destroys the sound, but I'd still wager that Vincent's shoes here make a headache-inducing sound.
The tutorial is so needlessly lengthy. Having Reeve as the tutorial-man is a hilarious contrast to himself from the PS2 game, where he rarely broke the fourth wall in this way.
Very uninspired gameplay, with barriers appearing at random spots with no rhyme or reason, even moreso than in the PS2 title. Interesting difference from the full game is that there are now these "Beast Spots" that transform Vincent, instead of a "Limit Breaker" item.
The Deepground soldiers... By the gods. For such a short game they sure managed to make the soldiers a helluva lot more talkative than in the full game. Soldiers are just standing there, holding conversations with the innocent citizens they are about to kill. It's like Deepground forgot that they were coldblooded killers! There were a few odd, similar moments in the PS2 game, but the mobile chapter takes it to a whole other level.
Rosso's "exit" animation makes me gawk. She just jumps straight up in the air. Not jumping forward, not backward, just...flies off. It's such a lazy animation that I can't help but laugh.
Then we have the researcher...who looks almost exactly...like Lucrecia Crescent. When I first read the game script on FFVIIExcavation, I thought they went for something a bit more subtle with this researcher. BUT NOPE! To a 95% degree, she IS Lucrecia. There is absolutely nothing subtle here when using her as a ploy to remind Vincent of Lucrecia.
Speaking of our favorite crazy lady... The PS2 game already did a well enough (unintentional) job at showing how insane she is. Her guilt over the death of Vincent's father kept her from embracing Vincent, yet she still invited him to a picnic and acted slightly flirty. The mobile phone episode however, yet again, takes things to a whole new level. She asks Vincent to dance with her, thanking him for saving her from her own obsession with scientific research and acts VERY flirty this time around. This scene made Lucrecia approximately...five times crazier than she is in the main game.
Dirge of Cerberus: Lost Episode. A game so bad that it actually gets a bit fun, despite the high headache-inducing factor.
EDIT: Vincent's acrobatics were cool though. That aerial battle at the beginning with Galian Beast kicking ass...kicked ass!
