I still find the display quality surprisingly good for a game of this type when I maximize the window and the game runs at 1280x987...
Yeah, it's a bit stretched but it still looks pretty playable! (I also love the choice of Comic Sans as your OS font, lol)
GMS2 will probably fare even better in this regard, in my current project I started playing around with SDF fonts and the way they magically get higher quality in fullscreen is amazing, this will make GUI design a lot easier in the future.