I'll throw in some more updates
Muramasa - 20 hours to beat (roll credits for both characters), I'm at ~24 hours right now and I'm close to 100%, so 28 seems about right for max
Professor Layton and the Unwound Future - 14 hours to get 100%. I wouldn't know the minimum time to roll credits because I never leave a puzle unsolved
If I booted up my PS3 I could add 3D dot game heroes and ACII times, but whatever.