Perhaps I've missed the point, but I'd always expect a "minimalist" framework of any type contain less code in itself but require more application code. That's practically the point.

You have to write more boilerplate, but at least you know what all that code is doing because the framework is so easy to understand. By contrast, a more heavyweight framework lets you wrote less boilerplate because there's a helper function for every situation, but then your application code is filled with lots of magical calls into the framework, so to understand your code you need to look at a different bit of the framework documentation for every line.

That's not to I say I think either is better or worse, just that those are the expected trade offs.

Of the two example games that come with the engine, skiing is 113 lines long and snake is 158 lines long. Both include comments and don't make any attempt at a brief style of coding, so their lengths seem reasonable to me.

What games have you seen that you feel are too code heavy, written using this engine?

"Code heavy" of course in a relative sense. You can definitely make a snake game with the same aesthetic in less that 158 line, and you won't need to carry along the engine. I would also argue that the plain javascript version will be easier to understand as you will not need to understand what the engine is doing.

What complexity do you think this engine adds?

It isn't forcing you to do any extra work, it just saves you from having to worry about setting up a canvas, listening for input, or running a timer. That's literally all it does. And it gives you a neat aesthetic with the grid of dots.