For many reasons.
The phrase originally comes from Douglas Adams’ The Hitchikers Guide to the Galaxy, where after integrating several years of Ford Prefect’s research and reports the guide upgrades Earth’s entry from ‘Harmless’ to ‘Mostly Harmless’.
We’ve always been a big fan of Adams*, who apart from being very funny was also fascinated by computers, and wrote a couple of very well-adapted games: The Hitchhikers Guide to the Galaxy, one of the finest text adventures ever produced (available to play online here) and Starship Titanic, an ambitious but flawed pre-rendered adventure that still features some excellent game-narrative tricks and gags.
So, it is in part a tribute to an early writer in the medium whose work we admire.
However, in a computer games context ‘Mostly Harmless’ is also a reference to Braben & Bell’s classic space-trading combat game Elite. The player was awarded various ranks to show their combat skills, the first of which was ‘Harmless’. After several hard-fought battles your reward would be upgraded to the splendidly back-handed ‘Mostly Harmless’ – itself a reference to Adams, thus introducing a gag in the space of two words.
Elite was a brilliant example of squeezing a lot of narrative value out of very few resources. Squeezed into just 32K (about the size of this web-page) every word had to really work to justify its inclusion. Elite had not only these rankings, but names and descriptions for each of two thousand planets in the game cunningly created by stitching together word parts and descriptions. All told, an incredible piece of work.
So, it is in part a tribute to an early game we respect, and one of us likes.
Overall, though, writing in games is often seen as a small and peripheral element, hence harmless. It’s a side-effect of publishers wanting to be equivalent to Hollywood studios, forgetting the potential advantages of their chosen form.
Through careful use of professional and experienced writers working together with developers who care about every aspect of their production, we can achieve the lofty heights of… Mostly Harmless. It’s a step in the right direction.
Also the domain name was available, which has a lot going for it.
* (Andy) Although I actually prefer the Dirk Gently books. I met Douglas Adams once – at the Digital Biota conference where he gave the speech reprinted after his death in ‘Salmon of Doubt’. And, although we admire his work, we don’t subscribe to his philosophy on deadlines.