In addition to making a game engine (which might turn into a fully-fledged educational game), which supports other ways of making levels, I wanted to make a tool that provides an alternative to doing everything in an IDE. So I'm not just making a game, I'm also making tools that make it easier to work on the game. This can be applied to other areas of programming too, not just games. Bootstrapping and extensibility are powerful concepts.
The level editor can be used in conjunction with the debug mode and noclip mode to make it easier to work on levels.
There are only a handful of tiles right now, but it's not hard to add more later. And these are just placeholder graphics.
The point here isn't about a game, the main idea is that it's good to work on big and ambitious projects to help you learn more about programming.
You can check out the game engine (with the level editor built into it) here on GitHub.