I think for the behind the scenes video you actually should have shown in-game footage, rather than just you playing around in the editor and with water. You also definitely should have taken out the part where your mom walked in, along with you broadcasting your sister had phone call.
Everything in the editor looks pretty decent. On the level in the streets, I'd take out some lights. Streets in London never have that many lights (at least not the various ones I walked on). The area where you said you were following the Soviet, you should make the level a bit bigger. From the looks of it, there were no enemies, thus making it appear that the level will last about a minute (which is how long it might take to load, knowing FPSC).
I'd also recommend not claiming that this game will be "one of the best FPS Creator games ever." It doesn't look too good when you're saying that even though no one but you has played it. If you were, say, quoting someone who reviewed the game, then sure, by all means use that quote. But don't just say that on your own.
Hope this all helps.
Cheesehead for life.
