The settings panel allows the theme, font, and font size to be changed. I found DejaVuSansMono looked best. A preview is displayed in the same view so you can easily see what each option does.
I tried it out with some of the bundled libraries -- impress.js for example worked fine, and I made a quick scratch project just to get a feel for the basics.
One of the best features in the app is the keyboard. Much like other text or terminal apps, it includes a bar with commonly used keys along the top. It has a button in the centre which can be used to move the cursor around easily, and the other keys have gesture-based punctuation shortcuts which are great for quickly inserting quotes and brackets.
I noticed that one of the Kodiak developers has a GitHub account with some polished-looking Objective-C projects: Adam Horacek. This includes the cool keyboard found in the Kodiak apps, which is KOKeyboard. Adam's work is definitely worth taking a look at if you do any iOS development.