The problem The Rollup SDK solves

Writing a specialized single-purpose rollup is unnecessarily hard and seemingly not feasible, and it need not be. We tried to bridge the redundancy of writing a lot of boilerplate code by abstracting out most parts of building the rollup.
With The Rollup SDK, users would be able to build specialized single-purpose rollups by simply adding their own configuration details and their own state transition functions.

Challenges we ran into

We are working on the bleeding edge of technology, and there is little to no information available on how to go about b building something of this sort - it was mostly fudging around and figuring out which parts to abstract.