Your show = performers + audience + space
The impact of the performers on the show is pretty obvious. The team with which you're playing is also important on your input to the show. If you're really there to support your partners, then you play very differently depending on who you're sharing the stage with.
Then, we all have felt the difference between playing for ten people or a hundred or perhaps even a thousand. But there's also the difference between playing for children, in front of people with different native tongues, specialised audiences at companies, etc...
Finally, in improv, the so-called fourth wall stands behind the audience, not between the audience and the stage. Use the space in which you are performing to the fullest, let it shape your show.
Obviously, playing in a bar will result in a different show from performing in a grand theatre. Yet, wherever we are, we should always check out the performance space before the show and during the show not be afraid to push the boundaries of what we call the stage.