Ah, gotcha. And yeah you're right, those were both very metroidvania examples and not true puzzle platformers... so I can't think of any either, at least not retro-style... guess I like some shoot-em-up mixed in with my puzzles.

Zombie Shooters advantage is that you have a brain-dead AI. Move towards player in the most direct route, which does usually mean getting stuck into walls. Then you have the balance issues, mostly concerning weapons, supplies and power ups. Not sure I'd call them easier to make than adventures or platformers, though it does depend on each developer's strong suites.

What I mean by "clout", is that the larger GOG's game catalogue is, the more customers they draw in, the more successful the business model appears to be and then from that they can take the demographics to larger studios as a compelling argument to embrace the platform. The games themselves don't have any clout.

Holy sh... it actually is. Somehow I was convinced that it's a top down action adventure, Zelda style. I actually bought the game when it was on sale once but never bothered playing it because I haven't been in the mood for top down action adventures since. And it's actually a platformer... oh my...

After Braid got all the insane praise every indie developer and their mother has been trying to create the next braid. The problem with this is that Braid was not really that good of a game to begin with, people had to be guilt-tripped into buying it. All those other puzzle-platformers in turn are just mediocre imitations with a different gimmick and "art style". At least Braid was one of the first ones to do it.

As for adventures, as other have pointed out, they are easy to make. once you can get sprites on the screen and make text boxes pop up you've programmed it. All that's left is writing your pretentious story and drawing the backgrounds. Actually, you can scratch the last part if you go with RPG-maker style sprites.

because they are fun to play

Yeah I've noticed that there are quite a few indie "puzzle-platformers" being released every week that fall under one of two categories 1: black/white/gray moody art style with a sad story or 2: Overly difficult just for the sake of being difficult. Obviously there is some market for them or else there wouldn't be so many of those games being released nearly every other day.

I've also noticed a lot of indie roleplaying/rogue-like games being released lately.

I haven't gotten excited about a GOG release since Wasteland....
Oh and Greatest Battles...