I thought about The Cave too. You have simple verbs only (like Pick up and Use). You have a simple inventory (maximum one object per character).
But on the other hand: The puzzles weren’t that hard. It was more about experiencing the story and environment.
To be honest, for me The Cave was a “puzzle platformer” and not a “real” adventure. 
And:
But it’s a good game. The only game I bought on Steam…
Hehe. We are fans - we have to!
I admit that I’m a little bit too deep into UI design. But I really like to know why which decisions were taken - especially if I think in an other direction…
Zak improved on this by having you open the toolbox and getting several different tools for different purposes out of it instead of just having you use a toolbox to fix everything with.
But wouldn’t now the “repair” verb make much more sense? Now you can repair the wire with the knife, etc.
Yes, and it was also great that you could just cleanup you inventory again by closing the toolbox!
I agree, The Cave is a great game BUT I say it’s an Adventure game because there is just no real platforming in it. It was about traversing the world like when you play TWP with direct control.
You mean “Repair … with …” instead of “Use … with …”? I don’t see enough difference in those two actions to make a distinction.
Maybe, yes
Agreed, the fact you cannot die from falling (and are only set back a bit) greatly reduces the platforming aspects.
How often do you have to jump in TWP? For me the controlling scheme and the level design in The Cave is much more like a jump and run game (have a look for example at Trine that has a similar structure).
“Use … with …” can also mean: “Destroy it with”.
This is valid for most other platform games too.
Whatever it is, it’s not just clicking on things randomly until you beat the game, it requires a great deal of thought.
Hehe, yes. Agreed. 
Many times. Hey it wasn’t easy to pick it up!
Use is a very ambiguous term but so is Repair! And every time I could (should) use the Repair verb it’s hard to explain to a player why he cannot use the Use-verb instead!
Well if I had my wish the next game would be a Metroidvania. Controls would be like The Cave, you can explore freely, and there is a great deal of dependency based on the items that you find that enable you to explore certain areas.
Did you know that “Axiom Verge” was done by exactly 1 guy? Maybe that´ll be the way.
That’s true. The advantage is that it streamlines the game, because you find the correct verb earlier than you would if all verbs were visible throughout the game. Hence, the developers don’t necessarily reduce their freedom in designing puzzles when they reduce the number of options for the player.
Deponia Doomsday, which I mentioned above, did take advantage of this method, too. Though, when I play such a game, it feels arbitrary that you cannot look at some items, for example. I admit that the nine-verbs interface has such limits as well, as you often receive universal responses when you try different verbs, but I think that it’s just more fun for the player to have seemingly all freedoms. And, it offers the developers more opportunities for inserting a few additional jokes in the game, or for making the virtual world feel more complex than it actually is.
You mean that ∗beep∗face who made a great game but didn’t release a DRM-free version? 
Not being able to even let my character look at items is really something I dislike in Adventure games.
I disagree
It’s not clear from the current state, e.g. how would you open it again to put another item in the microwave? (based on a real puzzle 
)
Possible solution (like you have suggested with the trampoline) is to use different hotspots (door, control panel).
And it may work well with slightly complex devices/machines.
With more simple ones (e.g. trampoline) splitting it into multiple hotspots may not be such a good idea, another example being door + separate door handle/lock hotspot.
Especially hotspots in another hotspot may be easy overlooked by players I think.
But if you do multiple hotspots maybe it is better to clearly name them?
E.g. when you allow to move an object like a trampoline or a lever maybe name the hotspots e.g. “left side of lever” and “right side of lever”.
This makes manipulation with a move (pull/push) command much less confusing.
It may not look that pretty though…
Would this be a feasible way to implement move-puzzles?
Could be money reasons, because it´s only one person?
Thousands of reviews on Steam, mostly positive: It’s not like no one buys this game. He just doesn’t care enough to make a DRM-free build and upload it on itch.io.
itch.io is a mess. TWP isn’t on there either. If you’re on itch.io, you need to make your own Windows installer (Steam/GOG do this for you). Not rocket science, but it’s a hurdle. And you have to set up your store and make a bunch of images in formats very different from Steam. Puting a game on a store is a pain in the ass. Plus, you probably have to do a different build if you’re doing anything with Steam APIs (achievements). Now you’re managing 2 builds. And you have a new place to monitor comments and do support for.
Read this the section “Zero Friction for Developers” in here: http://www.fortressofdoors.com/so-you-want-to-compete-with-steam/ This is real and every developer I know hates it.
I think it’s unfair to say he doesn’t care. He just doesn’t care about the same things you do.
Have you ever looked more into the specific reasons why that is?
BTW: I was surpised to see physical copies of the game at a local store last week (with all the pixely glory on the cover no less!).
You can release digital content however you like. Just upload a ZIP file.
(but tell the people about fancy prerequisites like Visual C++ runtimes… )
I understand. All those different platforms and stores are a pain in the ass. And selling on PC stores other than Steam may not be that lucrative.
Btw. I have read this article before and I’m wondering why you said itch.io is a mess, it got quite some praise there?
Is it?
Axiom Verge was initially released on 2015-03-31, that’s nearly three years ago.
As of now it was released an many different platforms: Windows, MaxOS, Linux, PS4, PS VIta, WiiU, Switch, Xbox One.
If he would really care about DRM-free software I think he would have found a way to release the game DRM-free until now. It doesn’t need fancy achievements etc., just don’t strip any essential stuff from the game.