I hit a bug that prevented me from playing, and then I found another. I have to dock some points for that.
I really like the idea (I mean, I made a detective game for this jam too ;-) ) and I thinks it's original too. Simulating the phone's UI is brilliant. The game feels complete, even without music: given the limitations of N3310, I think it would get grating quickly and I would turn it off anyway. The ring tone was spot on :-)
Probably my biggest complain is the font: it's just too small. I completely understand wanting to get high information density in your detective game, but it's your main user interface and it's just hard to use. If you are gonna work on the game in future, please, add at least one row of pixels.