The app allows adjusting colors (contrast, exposure, white balance, saturation, etc) applying dozens of effects, it has tools for painting (100+ brushes, stylus support, smudging, etc), retouching (sharpening, lightening, etc) and graphic design (texts, shapes) and much more. All supporting layer-based and often non-destructive editing techniques.
Because Pixelmator tries to include as much functionality as it does, a lot of time is spent navigating through menus, finding the appropriate tool for the job.
At a high level the interface is organized into broad groups of tools called Personas. Personas like Photo for in-depth image manipulation, Liquify for warping the image, Develop for basic RAW photo development and Export for exporting. Each persona displays only those tools that are needed for that task.
The interface, especially the Photo persona, is laid out in way that's very similar to Photoshop - a panel for icons for tools on the left, a panel for information and settings on the right.
Projects can't be moved directly between apps, they first have to be saved to the Creative Cloud. This also means that if you're disconnected from the Internet, you can't share projects between applications.
The app doesn't overwhelm you with functionality or hide it behind unlabelled icons. It displays about 5 tools at a time beneath the image and allows you to swipe through the complete list of tools horizontally. Most interactions with the software are kept in that bottom row so you can always see the results of your image manipulations.
There are 20 tools for image manipulation. They allow you to change the sharpness, crop the image, apply filters to it, add frames, etc. There are also tools for one tap redeye and blemish removal.