Great first effort by Russ, but it can be made better.
1) No need to click back 30 times from the end to the start, we just need a "Go To Start" and "Go To End" buttons. Important.
2) Sometimes, it can be nice to sit back and watch the line unfolding without having to click. Chesspad has an automatic forward function, so you click on it and the software plays through the continuation with a short delay for each move. Not important, just nice.
3) There needs to be a way to store branches. If on move 20, you explore a continuation starting with a3 and go 5 moves deep, and a line with b3 going 5 moves deep: when you review your analysis, you should be able to choose which line to explore. Just a little important, but very nice.
4) The pgn from the current game position to where you are in your calculations should be displayed on the analyse board screen. If I find a nice line, I like to record it. Now, I have to replay over the line and write the annotation myself which is quite slow. I should just be able to copy the pgn which would be on the analyse board screen. Very nice and quite important.