This was in fact, a great game. It took me like an hour and a half to complete, but then again, when I play this kind of game. I like not only completing it, but also making sure that I got every clue there is, and see how every character responds to all of them so I don't miss a thing.
In the end I had it down to 2 suspects, and I couldn't figure out what I had to do with one of them (the other one being the killer) to get it to say 'innocent'. Turned out I hadn't talked about every topic, kinda frustrating, becuase the suspect didn't really say anything very important to make it go innoncent.
Graphic-wise, well, you did a good job on the characters, they're all great and allthough they're not very animated, they still feel right, in some way. The backgrounds look very cool too, but I'm not so fond of the lighting, when I looked at the making-of, the non-lighted backgrounds look much rawer and cooler to me. But they were all still pretty cool.
Sound was well good too, got pretty tired of the moaning sometimes, but overall, it was okay. I guess you can't expect you to actually have real voice acting as it would boost the flash-size way up and have a hellofalot work, but this way worked too.
Interactivity is most important in a game. And allthough there were some things that annoyed me, overall it worked very fine. The whole get-the-truth thingie was a bit stupid, as it was just moving your mouse to the right when the screen flashed. It would be better if you had to guess yourself when the person started lying, would've made it more interesting. I also got annoyed by the text pausing at full stops and such. It appeared to me as if the characters line was over and I could go to the next, but then there was another line. Having the text just go through would make much more sense to me. The mini-games were a very nice add. But overall I could say that the game could/should have more difficulty in it, a more difficult 'get the truth' minigame would've worked. Or something else that could make the game harder.
Anyways, there's a lot of things that could be better, but you'll always have that. You thoroughly entertained me those 90 minutes and I look very forward to see a Detective Grimoire 2. But make him wear a hat then, 'mkay?