It really depends on the role you are looking for. If working with data and doing analysis, you need some knowledge in stats and probability. If you are working on simulations, you will need basic calculus and algebra. If you are looking at game development, you will need basic trigonometry and vector arithmetic. The one thing you don’t need is mental arithmetic because you have a computer.
That being said, you can get by without these skills, it just becomes harder to see what you need to do, even if you would know how to implement it. This is alleviated if you are working in a team however.
That explains a lot. I played Grim Dawn and thought that it took a lot of inspiration from Titan Quest, especially the levelling system. Never put 2 and 2 together though.