More Letters: An incremental cryptography puzzle game

I have been working on this project for a few months now. I posted in a couple of the Feedback Friday threads which where tremendously helpful. After taking some time off, I finally buckled down and finished the game. It doesn't include all the content that I was hoping for, but it includes the core ideas that I envisioned. I guess it just leaves the door open for future updates. The mechanics of More Letters are simple. At each phase you are tasked with delivering a certain number of letters. Before a new phase, you are given a choice of two of three different powerups that influence how you will proceed. On the fourth phase you are presented with a puzzle in the style of a cryptogram or something similar. At its heart, More Letters is a game about solving text based puzzles. There are 27 different puzzles. With each puzzle explores a different idea. Some build off of other puzzles and some are much harder than others. The order in which you unlock the puzzles is determined by how you play the game. I don't think this game is for everyone, especially people who aren't into cryptography and/or cryptogram style puzzles, but some of you may find it interesting. Any thoughts/concerns/suggestions would be greatly appreciated!