Played this one until I unlocked the full map but not those final upgrades. Definitely kept my interest.
The time manipulation elements were of course, the most interesting parts of the game. In a lot of similar games, usually it's just more complexity added to the economy. But with this game, the obelisk acts on a different vector which is time. Time can affect building speeds so it's not just a direct supplier of $ to the player. Great way to set up your economy!
Overall the game has good variety of systems that ebb and flow between each other to keep the variety going. You might switch from upgrading buildings to building new ones to switching over to obelisk upgrades to saving up for a grand upgrade that will change your next direction. This variety was very important and definitely gives you a Factorio-lite feeling.