XOut Clone - Shop System

I am working on a clone of the pretty old (1990) amiga game "X-Out" for quite some time now. It intended to be an exercise to get comfortable with XNA Framework.

The most current features I am working on is "some kind of laser beam system" (I should trademark that) and a shop system. Here is a first "design":

A basic "design" how the shop should look like

The basic idea is to use the normal in-game ship movement/rendering to perform the shop tasks (buy/sell items). This is be done by adding items (buttons) that can shot at with the ship's cannon. Player can navigate up/down through items owned to sell them and items offered by the shop to buy them.

To the bottom of the screen "some kind of laser beam system" shields a testing area from the rest where the user can "test use" the recently purchased items.

In-game graphics of the shop

Yes, I know, the colors are pretty nasty. But for testing I need clearly distinguishable colors to place buttons and other visual elements correctly.

So far, navigation through items is working, buy/sell is still a to-do. But the laser already works (but is not yet included in collision detection tests). Also, I'm in need of some ideas for some more extras (especially for the visual design part of it) and how to integrate them in the game configuration files - up to now, pretty much everything (levels, ship design, weapons, enemies,...) is configurable in various XML files.