I like playing puzzle games on my phone and tablet. Now that I am retired, I thought it would be fun to have a go at writing some of my own but I didn't fancy using expensive or complicated development systems to do it.
After looking around, I discovered Godot Engine, a free and open source system which can export to multiple platforms - Apple, Android, Windows, Linux, web...
I have found it relatively simple to get to grips with. If you fancy writing a game (or maybe some other type of app) take a look at https://godotengine.org/ .