The first step was a series of gamified tests, the ones you've already read about. It's not difficult; you just need to be mentally prepped a bit to be up to speed. I wasn't, and I got a bad score in the sixth 'game' (out of seven), and it didn't let me continue.
The first step is the online assignment, the gamified analytical tests.
The following metrics were computed from 1 interview experience for the Optiver Graduate Software Engineering role in Amsterdam, Netherlands.
Optiver's interview process for their Graduate Software Engineering roles in Amsterdam, Netherlands is extremely selective, failing the vast majority of engineers.
Candidates reported having very good feelings for Optiver's Graduate Software Engineering interview process in Amsterdam, Netherlands.