My "level design" section is still a bit light. I once published something that you'd categorize as "folded level with organic keys", but it isn't translated in English so far.

Maybe you'll like the reading of http://sylvainhb.blogspot.com/2007/08/armaggedon-machine.html if you have played Commander Keen 5 previously.

I'll keep you noticed if I come up with something fresh in that area.

Chargin Chuck is definitely a complex enemy compared to a Goomba. It takes multiple hits to kill, but so does a Paratroopa from SMB. It's unique but not completely original. I wouldn't call them a mini boss, but the boss and mini boss terms aren't so important.

I read your article. You've got the right ideas. Each enemy in itself isn't too interesting. But when you group them, shape the level in such a way, and move them they become much more interesting. That idea is counterpoint.

Each enemy in itself is threatening to the player in different ways. Some move and others shoot. Still, some can't be defeated and force the player to time their moves carefully.

You pretty much covered most of Donkey Kong enemy design well. It's not much of a game/platformer, so it doesn't get much more detailed/deeper from what you've covered.

Good job. If you want me to read anything else just let me know.

Btw, i once wrote a post on ennemies in DKC2 and how their "variety" was the key interesting element of the game. I'd be honoured if you'd like to give me some comment on it : http://sylvainhb.blogspot.com/2009/06/interesting-platformer.html

Nice week-end to you.