Here's a description of Digits direct from the iTunes store. My comments are at the bottom:
"Digits is a hypnotic new numbers game.
Clear the board by decreasing all numbers to zero. Tap to decrease a number and the numbers around it. Be careful though because numbers in isolation cannot be decreased. Order of operations matters. (Yes, just like in school!)
And, you'll be solving puzzles along with a soundtrack entirely composed by one of Simple Machine's favorite artists, Mokhov.
Play the first 100 levels for free!
Then challenge yourself further by landing on the star tile.
If you like it, there are 500 more levels available as in-app purchases"
1. The game is similar in theme to Lights Out. Which is a great and fun concept.
2. Digits is almost the exact reverse of Logisquares http://gottasolveit.blogspot.com/2013/06/logisquares-puzzle-app-game-for-iphone.html
which I reviewed last year.
3. I solved the first 15 levels in about 5 minutes. I think these puzzles are too easy. But that's because I really got into Logisquares which is harder for one significant reason, which I won't get into here.
4. The bigger grid sizes are harder, but they're still easy. My task was to solve all 100 puzzles as fast as possible. Altogether, I solved them all in about 25 minutes. Once you solve all the puzzles, you can redo them and try to get a star. A star will appear on a certain square and you will earn it if you make that square the last tap on the board. Nice concept, but why not put that at the beginning?
5. I don't know who Mokhov is. I always turn the sounds off and listen to my own selections.
6. Give Digits a try. Then go to Logisquares.