As soon as 16:9 screens were begun to be produced, 4:3 screens were stopped being produced for a long time, with everyone and everything using a new 16:9 screen instead of an old 4:3 screen.
Now we even have wider screens with aspect ratios of up to 24:9. There exist Even Wider screens, but they are so niche that I decided that my game does not need to support them.
But now, 4:3 screens are being produced again, on devices such as modern Laptops and Tablets. For immersion, I want my game to support not just a Single aspect ratio, but a Range of Aspect ratios. This range is guaranteed to include anything from 16:9 to 24:9, with 21:9 being my main targeted Aspect Ratio.
This is how the game looks like in 16:9:
When I tested my game in 4:3, it revealed too much content, which can be seen by the hidden path above that is not visible in the 16:9 version:
This makes me a bit concerned about my Aspect Ratio choice, because I made that choice when I thought that 16:9 to 24:9 was the Entire Range of common screen aspect ratios today, because I thought that 4:3 was only used by old devices which became obselete a long time ago: - How many devices which are important for (both hardcore and casual) gaming have a 4:3 screen? - How annoyed will players react when they see Big Black Bars at the Top and Bottom of their 4:3 screen?