CrystalBlend 0.99 is not very mature at the moment, Shawn. I found it lacks certain features desirable for a first person shooter, such as sound and character animation. They're available in CrystalSpace however, but it takes a good deal programming experience to execute the translation from Blender to CS.

If you like using Blender, then by all means check out the existing Blender game engine which can render a 3D FPS today. Blender game programming support is available at Blender3d.org, several forums like CGtalk, Elysiun, and in 'the official blender gamekit book'.  Maybe CrystalBlend will be more developed by the time your game is nearing completion, so that you can simply make the modifications necessary to run it with Crystalblend.