Well, your screenshots show the window size has changed, so presumably you have not set up support for multiple screen sizes properly.
I used the supporting multiple screen sizes tutorial to setup multiple screen sizes. I can't post a link here but here is what it says:
[quote:26qktumn]A common misconception is that you need to target a specific resolution, like 1280x720. However, there are so many different resolutions used that it's ridiculous to pick just one. It's much better to pick an aspect ratio, then scale the game to fit that. For example, instead of 1280x720, target the 16:9 aspect ratio. (Just enter any 16:9 resolution for the window size in Project Properties.) Enable Letterbox scale in the Fullscreen-in-browser project property, and now your game should appear correctly on any 16:9 resolution. If the display is not 16:9 then black bars appear down the sides, which helps prevent unintended display issues like accidentally seeing too much of the level or menu screen. Note if you are designing a pixellated retro-style game, you may want to use Letterbox integer scale instead.
The rest of this tutorial will cover the tools available to you in more detail. It's still worth reading even if you use the quick solution above. You can even support different aspect ratios if you are willing to design your game more carefully.