After considering a few different systems, I decided to just go with the old grade-school A, B, C, D, F system. But what does that mean for apps? Here's a handy summary of what I consider some representative ratings:
A (recommended without reservation for all gamers): Carcassonne; Cut the Rope; Axe in the Face
B (somewhat flawed, or intended for a limited audience): Undercroft; Cribbage King; Roll Through the Ages
C (some good elements, some bad): Crazy Parachute; Urban Ninja; Splode; NCIS
D (simply bad in almost all of its particulars): Deer Hunter: Bow Master; Pocket Frogs
F (incompetent or aggressively awful): any Zynga game; Zombie Dice; Ugh Find It; all zit, fart, sudoku, and Katy Perry apps
That breaks down to:
A: Excellent game.
B: Good game with problems, or a game meant for a very small audience. For instance, you may well make the best simulation the world has ever seen of trainspotting in East Anglia between 1894 and 1899, but it's still not going to get an A. Life is cruel sometimes.
D: The developer really should consider another line or work, such as human test subject for dangerous and/or potentially lethal medications.
F: The developer hates you and all life and probably drinks a breakfast shake made of blended puppies every morning.
I probably won't do a lot of D and F reviews, not because I'm afraid to take a game out to the woodshed and lay a switch across its hindquarters, but because most games that fit that rating simply aren't interesting enough to review. The app store is full of low-rent garbage that simply can't sustain a whole review. Unless I need to put in some verbal bag time to keep my writing up to snuff, I don't usually bother.
I also won't be doing half-grades ("+" or "-"). Five grades are more than enough.
By the way, I'm calling it a "Grading" system rather than a "Rating" system because the word "rating" is used as a gauge of content by the ESRB (Rated: E, E10, T, M).
If you are a developer, fan, or PR person who has a problem with any of my reviews or ratings, please take it up with the management: