CodeCombat is great. I trialed it last year with much success. The program takes students beyond an ‘Hour of code’as they continually want to come back and keep playing. You can sign up for free as a teacher, create a class and then give your students your ‘ Class Code’ so that they can join, hence, no need for students to disclose any of their personal information when joining.

I also trialed Grok Learning last year, using the paid subscription. The program is very well written and explicit, but it is missing gamification, motivation to learn by video game design/elements. Students would complete a level of Grok Learning and move onto the next level with minimal reward (except internal satisfaction of having completed a level).