Otto lab is classic Insomniac =]
I found the stealth modes very easy and they gave a lot of tips and directions. I do agree with the research stuff that were strange.
Yeah all the other stealth missions were easy.
I had to find a code, and I thought the date on the side of the Otto-Osborn pic was the code, and that I was supposed to punch it into the dialpad somehow to get into the secret lab. Then I thought that the painting of Mrs. Osborn had the key kidden somewhere in it. Next I thought that the key was hidden somewhere in the kitchen because "She loved to cook". I knew that according to Osborn's recording it should logically be hidden in a picture frame. But I just spent about an hour scouring the entire apartment until I finally found that picture frame. If it was a snake it would have bit me.