We just started this book a couple of weeks ago after finishing Explode the Code 1 and I am really glad that we are doing this before going to book #2. It is definitely a step up from 1 but has some overlap so that my five year old is still confident in what to do on each page. She still loves the drawings and silly sentences and is enjoying moving on the Explode the Code road.
My son has Apraxia of Speech & Dyslexia, which together makes reading and writing a BIG challenge. We started on book 1 1/2 & realized we needed to start back at book 1 for the workings of things & to build a foundation. I want to say that books 1 & 1 1/2 can be used together & I find they work better that way. At the bottom of each lesson in ETC book 1, it directs you to the pages of this book for further practice which makes them work very well together. You can also purchase the PAF series of workbooks to work with this system of learning for children with dyslexia. My only negative comment is like other reviewers, some of the graphics are hard to decipher.
I switched from Spelling Workout, which works great for my daughter, to Explode the Code for my boys. They just seemed to need more focus on phonics. The name, of course, excited them right away, and from there the simple exercises and fun graphics kept their interest. It seems to be working well so far.