Nicely *handled* episode, for the most part. The storyline stacked itself nicely*, and the expected Plankton-bashing wasn't the usual gooey mess we've come to expect (for the most part), *plus* it wasn't overdone. The humor was hit-and-miss, at least for me (fake-coppery just isn't my forte; Spongebob's jokes about it are).
Patrick being drunk on ice cream is priceless; the "rain from the toilet bowl" scene was better (and more innocent-feeling) than it should have; the "jailhouse ice cream" scene was neither, though alright by the plot (as it lets Patrick roam free). (Nitpicking, but at least remove the underwear.)
Overall, 'plain' good, or just above OK. ~6.75-7/10.
* As in, Spongebob and Patrick's side events with Krabs and Plankton building up to the evidence room scuffle. It isn't a one-way street in terms of plotting, as per usual; it's a reverse fork-in-the-road. Also, it's nice that they let the 'interrogation' scene pay off for the ending.