Question about 4:3 VS 16:9

I noticed that COnstuct's default screen ratio is 4:3, which I started making my game in. But I noticed that almost all screens nowadays are widescreen. Laptops, PC monitors, everything. I was going to have an option to switch between fullscreen and window mid-gameplay (assuming that Construct bug gets fixed), but that would just stretch the image out. Should I just change the game's screen ratio to 16:9? It'll be a little weird, since you're pretty limited on what custom resolutions you can have in widescreen, as I've discovered with some experimentation.

Also, speaking of screen changes, is there any possibility of finishing up that feature that detects all the compatible resolutions for a player's PC? I'd love to allow an option for window or full screen, and allow for the player to change the resolution of the game to anything their monitor can support, like most common PC games do now.

Does it matter? Most games are windowed nowadays, since desktops usually have a large resolution.

I was going to have an option to switch between fullscreen and window mid-gameplay (assuming that Construct bug gets fixed), but that would just stretch the image out.

Set the resize mode in application properties to show more window content.

A problem with this is that Construct doesn't really scale down a game that has a greater resolution than the window. A 1920x1080 or even 1280x720 game gets clipped to 1024x768 on my 1024x768 desktop, even with the latter stretch-contents-to-fit option.

Most games are windowed nowadays

O_o no they're not.

Should I just change the game's screen ratio to 16:9?

You can change the window resolution on runtime, there's a system action for that. You can choose any resolution you wish. Content, however, has to be adjusted by you (that is, if you change window resolution in runtime). Look into layout zoom. You may have to do some aspect-ratio math.

Also, think if it makes sense for your game to display in both 16:9 and 4:3, as level design can get broken when switching between them. If it doesn't, pick one and add black bars (or whatever) for the other.