This was a very charming id1 style mini episode running old Copper. A mostly linear experience across all maps but designed in a satisfying way with a good flow. The experience could definitely be altered for higher difficulties by adding more higher tier enemies, or just enemies in general, there are a lot of doors that never open that I expected them to be monster closets, and when it would have made sense to have monsters come out of said doors, they instead get teleported in.
What I thought the pack did well other than progression and artistry was making the player actively look for secrets by luring them in with minor things like a small window that you can't quite access or shooting triggers that either make sense within the game world i.e. shooting skulls in an "Egyptian crypt" in the style of DoE or buttons that are slightly hidden but they don't stick out like a sore thumb when found - it's playful in a video game-y sense and encouraging exploration is fun.
The moving platform puzzle thing in map 2 was great, it can definitely be brute forced/solved without thinking too hard about it or even cheesed by having the first platform be accessible, touching a plinth, rushing back to the first and as it gets removed carry on jumping, but that's fine. It would've been great if similar additional pieces were found in other maps, it adds something to do in between navigating the pretty environment that is in a slight need of more enemies/harder encounters.