Super Zero was quite nice to see Atchan despite the fact his "lightning speed" thing was irritating. Sunikura was so cool and I loved her voice too much, too bad it wasn't listed in the credots. I also enjoyed how Yumi was tolerating Atchan which I do believe is very humorous.
Artist Ami was quite nice because I liked Monet Renoir. I also think Kaz and Yumi had excellent lines in the episode to keep it humorous.
Ikkakujuu was the first non-vocal cartoon. The way it was handled was brilliant. The bubbles were possibly one of the show's best original work since "Mini-Puffs". Anyway, I liked the way the music and how the episode was handled. Even the ending was quite good.
Overall, this is my favourite episode of the series and I do recommend you to watch it.