Thanks! The key binding window is definitely an issue I had missed. If I hadn't just helpfully broken mouse support, you would also be able to click to rebind. You can also save bindings once and then edit the JSON in web storage if your browser lets you do that.
In principle the key targeting does take letters in order for enemies in view (or in hearing) but there is some bug that's preventing it -- actually now that I look at it I think it's effectively randomizing the initial queue after 'a', so I can probably fix that.
I would really like to work on this enough to add some differentiation and progression to weapons. I would also like to try to adjust infantry so they have more specific advantages but are less overwhelming. Unfortunately the code base is currently pretty messy, so I'm sure how far I'll get with improvements.