Ugh, that logo is way too big. 
I don't use dual monitors for developing. Do you actually play games on dual monitors? Isn't the split down the middle annoying?
You can set whatever window size you want in the options - just click on the current dimensions and type in something else.
Yes, I play games on dual monitors but not in the way you are thinking. I keep the game in my left monitor exclusively, and I keep my right monitor clear for any of the following: Skype, Pidgin, Chrome, etc.
And OK. I had no idea the size could be specified manually. I didn't look at it hard enough. I'll take a look at that when I get a chance tonight.
Yeah, I don't know of an ideal way to detect the presence of dual monitors. There is likely a trick specific to Xlib for detecting multiple displays. For SDL itself, the only luck I've had is to check the display size ratio and see if it is logical. Most games try to take both my 1080p screens using 3840x1080.
For what it's worth, the game functioned just fine in that huge window. The problem was that I probably saw too much of the map at once.