Humm
Well, Im not sure about a name, but you really need to look at your game and think: "What it looks like?"
If the game looks darker, if it looks crazy, or if it looks bloodly wild, you really must think about something that 'shows' the idea of your game, without being too much simple (I dont like "phybox").
Sim City is about creating citties! Prototype is about a guy who is a "prototype" of a experience and Too Human is about a unfriendly demi god who is 'too human'. There are some differences between the 'idea' of these games, but your names are created based in the same definition: They show 'something' without being Too Simple (Ok
Your game is a Physix Sandbox game, but, im fact, what do you DO in your game? Maybe it can help you to create something cool.
"Physix Sandbox" is something too much vague to define something. =\
Can you post some SSs?
