Overall it was a good episode, there are subplots here and there such as shaggy's desire for his hair to grow back to its normal length, daphne trying to move on from the gang, though she does offer some help during the mystery and fred using a teddy bear as someone to talk to and later as a surrogate daphne, which was slightly weird but quite funny. He seems to be the one going through the most changes this season as he struggles to cope with the loss of daphne and life without his fake dad. He's still growing and in the following episode he really steps up and saves the day, so i wouldn't despair as far as characterisation goes, he's still a little odd but getting better with every step. The mystery itself was decent though there were only two suspects and the plot behind it was slightly obscure. Mr E is a more visual presence this season and hot dog waters character was fun to watch with the gang.
'when you do things right people won't be sure you've done anything at all'- Futurama
Can I ask you something? Did Velma find a piece of the planispheric disc in episode 28? (because it's the only one I haven't found yet and because I saw a picture of Velma in episode 30 (I think) at the first minutes of the episode (it showed some pictures of the previous episodes) holding a new piece)
I think Velma was working with Mr. E for quite a while during the time the gang was split up. It explains how she showed up with martial arts skills and a voice changer. She used the changer again on the mission to Russia, where both she and Hot Dog Water also demonstrated great burglary skills. Mr. E had the resources to train them both.
This means Velma told the gang another lie when she said nobody had seen Mr. E. since the gang split up.
Which was cleared up when they met up in the house and she handed the piece of the disk to Fred. How much choice she had in the matter is unclear but given Mr E's behaviour I expect it was a offer she couldn't refuse.