A useful user interface, part 1: Play controls

As a professional "web guy," I have more than a passing interest in user interfaces. The most brilliant concept or the most beautiful design means nothing if people can't accomplish their desired tasks on the web. The same is true, of course, for any kind of application, serious or silly.

For SPUDZOOKA to appeal a wide audience, its play controls and graphical interface must be simple, intuitive, and easy to master. Frustration is the opposite of fun. I don't know yet if I've succeeded in delivering the fun, but here's a look (in two parts) at the basic process I used to design the game's various interface elements.

Play controls
SPUDZOOKA is primarily a target-shooting game, but it borrows a lot of its play controls from first-person shooters. The challenge is to keep the controls as streamlined as possible. Here's what the player needs to be able to do, and the reasoning behind the control scheme I chose for each task:

• Aim and fire the cannon -- The goal of each level is to destroy as many targets as possible within a set time limit, so aiming and firing is kind of important. Thankfully, as anyone who ever played a first-person shooter will know, the mouse provides a perfect interface for this: move the mouse to aim; click to shoot. Easy enough.
• Switch weapons -- Lots of target-shooting games stop there, but SPUDZOOKA lets you carry more than one potato cannon at a time, so there has to be a way to switch between them. Another first-person shooter convention fits well here: using the number keys to switch weapons.
• Switch ammo -- Yes, more switching. Clearly everyone knows that different spud cannons shoot different kinds of ammunition, so I had to work that into the game. The number keys are out for this one (even the higher numbers), since they are being used to switch weapons. I could map several letter keys to various ammo types, but that still seemed redundant and possibly confusing. Instead I decided to use a single button (tab) to cycle through all the available ammo types for the active cannon. The disadvantage here is that it could take a bit longer to select the desired ammo. However, because each cannon will only be able to shoot a few types of ammo, a cycling control seemed to work well enough (let me know if you disagree).

That's it. Seasoned FPS gamers (who made it this far) may have noticed that one important control is missing: the ability to walk around. Seems like a big omission, I know, but I have decided for the time being that the player will be stationary. I'm sure it seems limiting, but there are a couple of reasons for it.

1. The levels are small and potato cannons shoot a long way. If you can run around and shoot things, it might be too easy. Enabling really slow movement would probably irritate people. Better not to risk it.
2. I don't want to complicate things. A lot of the skill in FPS games comes from the player's ability to move and aim at the same time. I know this because I am quite inept at jumping while shooting in Halo, which seems to be necessary for survival in multiplayer mode. While plenty of people certainly possess these skills (they have all killed me in Halo), I don't want those skills to be a requirement for my game. I want to focus the player's attention on choosing the right cannon and ammunition for clearing obstacles and hitting targets, not on maneuvering quickly and dexterously through space.

Once you play through a few levels, you can tell me whether you're completely bored standing in place. In part 2, a look at the graphical user interface.