I'm not otherwise familiar with it, but the landing page linked describes Pact as 'a Turing-incomplete smart contract language'. Lurk could be used to implement

I'm not otherwise familiar with it, but the landing page linked describes Pact as 'a Turing-incomplete smart contract language'. Lurk could be used to implement smart contracts (with some glue connecting it to a blockchain — as we plan to do for the FVM), and we believe its characteristics will allow interesting applications in that domain. However, it's not inherently a 'smart contract language'. It looks like Pact considers Turing-incompleteness a benefit, since it makes it easier to reason about the cost of programs in a blockchain context. I don't see mention of zero-knowledge or succinct proofs, which are some of the more 'interesting' features of Lurk. For example, in a blockchain context, costs associated with program running time are less relevant for Lurk programs executed on chain because verification costs aren't affected by the running time of the program. All proofs created by a concrete instance of the language are verifiable in constant time. This is an example of how Turing-completeness and succinct proofs provide complementary benefits. It looks like Pact has a Lispy syntax and immutable data, so they seem to have that in common.