I've had a lot of fun fiddling with pico-8 (https://www.lexaloffle.com/pico-8.php), a virtual console with its own code, graphics and music/sound editor - heavily restricted (in terms of e.g. amount of code and graphics, it's designed so that games fit in an image file), maybe a bit more advanced than a Gameboy.

But being restricted like that made it feel more free. Don't need to think about function or variable names too much since only two dozen characters fit on screen. Graphics, just click some pixels until it looks like something.

But it's powerful enough to make games like Celeste (https://www.lexaloffle.com/bbs/?tid=2145) or even 3D games and demoscene things.