just be aware..you can't save your game progress whilst playing....
and i don't think there are many...(if any) people who have actually released an entire game. It has it's good points...but is currently quite limited. If you want to make quality FPS games, there are better game engines out there...
see this link
http://www.devmaster.net/engines/index.php
FPS Creator is a great 'toy' to muck around with, but if you are serious about game making, you may find it too limiting....and there are heaps of rude little brats in these forums that will trash you just because they know more than you and they like to show off how badly they spell.
check out these review too...it's a must....
http://www.devmaster.net/engines/engine_details.php?id=271
cheers..
munky
let he who is without aim cast the first stone.