The full game is flash, and it's capped at that resolution. Higher resolutions in "fullscreen" mode simply gives you a black surround. This is a game that will be played in a window by most.
Is it possible to enlarge the game window to fit in my big screen?
Unfortunately not, you can view the game only in 100% mode (1250x790px) or 80% mode (1000x632px).
That said, the art direction is wonderful, and the quirky humor is endearing. The puzzles sometimes take what I would call "creative" leaps of logic but overall I'm enjoying the game.
Also, "Do not use CCleaner or you will lose your saves" as the saves are stored as flash temp files.