>>381979381
There's a bit more. You can do side objectives such as finding specific rooms, taking photos of specific things, mapping the tomb, or finding gold for extra money at the end and so on. 

The main objective is getting the relic in the tomb, but in order to do so, you need to correctly determine what the mejai(read:ghost) is. You will have tools to help you determine that, which is pretty much like phasmophobia. If you guess wrong, you cannot get the relic, and you have to find the blue lever somewhere in the tomb to open the exit. 

If you DO guess it correctly, the relic room opens, which gives you the opportunity to grab the relic and go. Similarly to guessing wrong, after you grab the relic, you must find the blue lever and escape the tomb. AT this time however, the mejai will have physically manifested and will try to hunt everyone down for the rest of the game. Each mejai type has their own way of doing things. My favorite one is Dekan the Lost, which has very strong hearing and loud footsteps, turning the game into a stealth segment.