As a game designer at Zen Studios I designed seven digital pinball tables.
This is how it usually went: I came up with the overall concept once we got green light on a theme or IP. How the table should feel like, what would be the main features and some possible game modes. After that I drew a layout where every lane, ramp, post, bumper, etc. had it's place and the 3D artist started the initial modelling of the table.
Simultaneously I gathered references and came up with visual ideas so the 2D artist could create a concept art. I submitted a list of animations for the characters on the table so the motion capture (that's right!) could start. Meanwhile the game design document got longer and game modes started to shape up.
When the first rough version of the table became available I started to script the game modes in our own visual scripting language. QA got to write their first bugs for me to squash. Sound design was also my task: choosing and tweaking sound effects, music and writing the script for the voice actors.
After a few months the table got closer and closer to the final version. Alpha, beta builds were made, feedback from IP holders were considered and worked into the subsequent versions. Finally, as a designer I wrote marketing texts and made screenshots and trailers for the table or table pack.