The concept is nice with the puzzle aspect, but that is it. App does not say the blend sound, nor does it say the word when you make a correct one. There should be an option to turn sound on and off. If you can read already then why would you need this app. If the app gets updated where it says the blend sound and the word after it is made then this app would be more useful.
Practice over 800 words using 20 consonant blends. Pick a consonant blend/digraph then try and find 5 endings that create valid words. Drag the word ending down to the puzzle piece to check if your word is valid. See if you can complete all 20 consonant digraphs. Every time you play the distractors and the valid words will be different.