When I started making City, I wanted to do things differently. I had made a whole bunch of games where the control method was "Left click uses/talks/walks, right click looks" - a comfortable, effective control scheme that is very common for modern adventure games. However, I thought I should try to experiment. I had made a couple of short experimental games without inventory or right clicking for their puzzles (Heed and !) and I wanted to try to expand on the idea of having only a single mouse button with which to interact with the world, while still keeping inventory items.
My reasoning was this: For items that players can use, I always write a boring "It's a door" description for the look function, and for items that they can't it's always a detailed description of that thing with a "I can't pick that up" response for the left click. My idea was that I could get rid of the boring descriptions for the things that you can use, and remove the standard "Can't do anything with that" responses for the things that you can't. I would eliminate all pointless feedback - after all, I can *see* that it's a door. I don't need the player to say that aloud, it adds nothing to the game at all.
To counter the fact that some things I wanted to have both responses for, I developed a multi-purpose card that would unlock doors, allow you to buy things and the like. It almost became a sort of additional verb, albeit one that was stored in the inventory and only usable in a few spots.
The problem, however, was that every time you wanted to make a call now, or open a door, you had to mouse up to the inventory, click, mouse back down to the hotspot and then click again. This doesn't sound like much, but doubling the amount of clicks needed for simple, common interactions is pointless. I wanted to keep the look response, and yet I wanted players to be able to do these things (after the first time) with a single click. It simply wasn't working in a way that wasn't frustrating.
Another thing that made me realize the unsuitability of this type of interface for a game where I am trying to put in as much detail as possible was that, in order to have items in my game, I either need to make them automatically used by a player once they have them (not an option I was happy with in this case, though I've used it before), have a hotspot you can mouse over/click to clear the currently selected item (I've put this in an interface as an additional method, but don't think it is intuitive/simple enough to use as a primary one) or, the old standard, use right clicks to clear inventory items back to the standard cursor.
This meant that, although I'd removed right clicks from one part of the game, I still had to have them for this part, meaning that players still had to use the right mouse button. I hadn't actually streamlined my interface... I'd merely made it less consistent with itself and more frustrating.
And so, I went back and put in the right mouse button as the look button, and reworked the whole lot. To counter my initial issue of bland, meaningless feedback for various things, I'm doing my best to write more interesting descriptions for unused functions. It's not a perfect solution, but it's better than having a frustrating interface.
I've experimented with a few different interfaces in my time - selecting specific actions from a list when you click something, using a verbcoin, single mouse button without inventory items - and I still find the "left click does things, right click makes the character comment on them" one the easiest to design around.
I still plan to keep experimenting with them, but for now, this works fine.
