Yeah, unfortunately. I love the criminal figure. It's such a big part of Detective Conan. It's something that makes it special.
Anyway, back to M-15...
Three main scenes that were featured in the first trailer but did not appear in the second trailer were:
1. Haibara and Conan on the snowboard.
2. The DB flying off the cliff.
3. Ran calling for help.
These were the three main scenes that actually got the most mention, and they weren't even hinted at in the second trailer. Something is telling me that they aren't very important. That's just my guess.
My guess on the story plot is something like this...
A boy sees a person commit a crime. He is chased down by the criminal and falls and goes into a coma. Eight years later, he wakes up and barely remembers what happened. As he tries to recall, the criminal starts to target him. Somehow, the governor of Tokyo is involved and his dam is causing a lot of controversy. Conan manages to capture the criminal and maybe even knock him out cold, possibly with his soccer ball. But, the criminal already has a set of bombs attached to the dam, timed at exactly 15 minutes to blow up. Everyone escapes, except for criminal who may be trapped somewhere, knocked out. Conan, in a desperate attempt, tries to save the criminal. But soon Conan himself is stuck, and the criminal probably revives and helps Conan out, and both of them escape. The dam breaks and water floods the town, crushing everything in it's path. Luckily, everyone is already evacuated.
This is just my guess of the story. It's sort of like a mix of M-4, where someone's memory is lost, and M-9, where someone is trapped, who later revives and saves Conan.
Edit:
Just found a better quality trailer, for those who want to observe the details: Here it is!