If you run into the wall while pressing up or down alternately you can clip through the wall at this spot.
<img src="http://img140.imageshack.us/img140/6236/clipping.png">
You can do the same thing around this area as well (but it seems like you can only do it when the door is still locked).
<img src="http://img44.imageshack.us/img44/747/clipping2.png">
That game looks very nice, though. I'm looking forward to seeing what the aliens (I'm just assuming you'll be fighting aliens) will look like.