i must admit that loading times between levels takes time, but if you build the game carefully as not to use too many different entitys, too many lights and carefully build your world, it should keep it to a couple of minutes, make a nice loading screen with music maybe a message saying make a cup of tea!, but i think maybe the tgc guys could get onto this like they did with the x9 version. patience and dedication is needed and also if you send them a letter maybe they may consider this and work on speeding things up. but anger is not the way, just explore with it learn the script and maybe make models and play with it to see what is the biggest time eater in your game.
an unquenchable thirst for knowledge of game creation!!!