Season 2 was consistently great, but yeah the Pizzaface episode was the worst ep so far, and the Sir Malachi Larp episode was pretty weak too. Thankfully they're one-shot characters and don't appear again.
Other than those two eps I enjoyed every other ep of Season 2. Some were better than others obviously, but they were all good. The way they built up the Shredder/Karai story and the Kraang was done well, although it's going to go on hiatus for awhile due to the Northampton arc in Season 3.
If you're complaining about horror eps now, be warned, the Northampton arc goes on for 8 episodes in Season 3 and at least 5 out of those 8 eps are horror themed.
