In That Other Dimension is top science-fiction comedy, with larger-than-life characters and no small amount of ambition. Millard has a good grasp of how to deliver comic literature, specifically to always keep one foot on the pedal, steering the novel from chaotic set-piece to chaotic set-piece.
Comparisons to Douglas Adams are obvious and deserved. This is a great opportunity to hitch-hike across the the multiverse and, with Millard in the driving seat, you will be glad that you rode shotgun.
In That Other Dimension is available for Kindle and in paperback.