It's a cool concept, though it's also tedious to click on letters when decoding rather than typing them.
But...I have to admit I gave up when I hit "My name is Ash. I'm inheriting his work", not because it's too hard a puzzle, but because that's a lot of letters to have to type one by one while looking at the code and retyping if you get anything wrong. Especially without a backspace. It took me three tries just to get through "This isn't Caleb" in part because when I accidentally put in a space in the wrong place, I had to hit enter to start over.