Looks pretty similar to the back of our fridge here. I imagine most probably look like that.

The sealed black compressor compartment contains the compressor motor/pump thingie, suspended by springs to help keep it quiet. Three springs, apparently.

On our fridge, two of the three springs have broken or become disconnected. The result is a rather loud BANG-Bang noice when it switches on or off. It's been doing that for about 8 years now, and at some point we expect the third spring to give way.. and a new fridge to replace it.

Cheers