I guess I should update/add some of the Missouri listings as I am frequent visitor to most of them!
The Game Trader closed up. Another person came in, bought the store and the name and the store is now called Game Trader II. It is still very recommended as he caters to retro gamers. In fact, I've bought reproduction carts from him, so he is highly recommended.
Vintage Stock has come into town within the past two years or so. They have two locations, one in South County Mall and the other in Chesterfield. They are very much like Slackers. Slackers is a bit more pricier, but they have a far better selection.
Vintage Stock
25 South County Center Way
St. Louis, MO 63129
http://www.vintagestock.com/Prestige Electronics opened in the past two years or so. They started as a cell phone shop with some repairs on the side. Most of their business is console and cell phone repairs, but they have a decent selection of games. They are slightly high, but nothing too bad. Really nice guys.
Prestige Electronics
11977 St Charles Rock Road, Suite #125
Bridgeton, MO 63044
http://www.prestige-electronics.com/Arch City Gaming Company is a bit older and very under the radar. Their selection is pretty minimal, but he does have some rare stuff. He has a Jetson's NES cart sitting in his case for months. He's very nice and his prices are reasonable, but it's either really good or really bad. No in between here.
Arch City Gaming
12272 St. Charles Rock Road
Bridgeton, MO 63044
http://www.archcitygaming.com/There is also a store called Animeggroll, but they are mostly an Anime store. They do have some games, but not a ton. It's hard to call them a game store, but they have some strange titles that you don't see often.
I'm happy and lucky to be around 10 Vintage Gaming Stores all about 30 minutes apart from each other.