Mr. Plankton was a great watch that started out with very questionable beginnings. Even the characters called out the things that made no sense. I began to understand more, and it became more clear. They were flawed people. 
The acting was pretty good, even though I could do without some of the wailing like a 4-year-old. (flawed) 
However, the execution was decent. I enjoyed the way the series opened the worlds of these characters. I felt bad for Eo Hueng as well as Hae Jo.  Despite some issues I just had to ignore, Mr. Plankton was a bittersweet and engaging ride.