Take a look inside 5 images
Pros: It's built by educators and gamers, and kids can find the right level of challenge.
Cons: Could be frustrating for students uncomfortable with trial and error, as there are no tips or advice on correcting script syntax.
Bottom Line: These varied games are great for introducing the fundamentals and practicing but aren't sufficient as a complete curriculum.
Terminal Two is most useful as an introduction to coding and computational thinking, as an extension, or as a supplement to a unit. It could be used in the classroom as well as during an afterschool club or activity. Check out the PDF Educator's Guide (make sure to download it to get the full version!), which has sample lesson plans, to get some ideas. Since the Quests are sequences of self-paced games, you'll need to help students find the right place to begin.
If all of your students are beginners, start with the Quest "Thinking Logically," which introduces computational thinking and other foundational concepts. "The Core of Code" would be a good Quest to tackle next. The games themselves are a good way for students to practice what they've learned and build on it, but reading the text is important, so you may need to pull those pieces out to use for direct instruction. Also, note that Terminal Two doesn't seem to work on tablets.
Terminal Two is structured well for students to be exposed to coding concepts and vocabulary. Because kids can go through the Quests or jump into games, it's easy for them to find the level that's right for them. Plus, the games feel fresh and unique, and the concepts are embedded pretty well into each game's structure. Overall, the graphics and look and feel of the site will likely appeal to kids and make them want to advance so that they can play the more sophisticated games. Plus, adding the instructional text, questions, and real-life applications extends the learning a bit further, beyond the games themselves. Though it's not clear that teachers need to actually download the Educator's Guide to get all of the supporting material, the PDF has a lot of alignment information and ideas.
However, the overall organization of the site could be better. There's no requirement to complete any game or level; thus, the user can self-select any game. This may be beneficial in some cases but means that teachers lose a bit of control over being able to assess a student's level. Also, within the games, there's not much dynamic feedback, so students may become frustrated if they are unable to solve a problem. And, though the text has some excellent information, there are no reading supports and no way to know if kids read the text at all. Overall, Terminal Two may be best as a launch activity or as supplemental engagement, rather than as primary curriculum, but it is a fabulous free resource.