I've been using a dedicated program to store all my games and it's been lacking lately (they have a DB that supposedly tracks games so that they can easily get the data from their server, but lately it's missing games, even big titles like Grand Theft Auto V). I've been considering several options for a new way to store the info (this site, plain spreadsheets, SQL database, even a full site to add and track them (although if the opportunity came up I'd rather work on a existing site rather than trying to build a database from he ground up)).
Anyways the application does have a few features that I don't see here that I think people could get some use of.
First, you have Purchased Date, but how about a text input for location purchased?
A way to track if you've completed a game or not (a simple checkbox is what the app I'm using has, but I think it might make more sense as a drop down, so you can denote if you just beat it, or if you went for 100%, as well as denote games that can't really be "beaten" (like atari games, they could have a high score system to track your highest score however).
A "location" field, this one is probably the single biggest thing preventing me from making a switch, since I have all my games in boxes (I don't really have the space to display them anymore) I've been making extensive use of the custom field to note what box there in so I can easily find them when I want to play them.
Those are the features that I've noticed that I think people may get some use out of and should be easy to implement (in fact, if you have the site up on a revision control system I'd be happy to make them when I get a chance and push the changes to you if you'd like, I'm guessing that the site is built on a standard LAMP setup using the Twitter bootstrap and jQuery, happens to be my usual stomping ground so the only problem would be finding the time).