Unboxathon is a simple, relatively short, clicker game. In this one (and I feel like I’ve played a lot of these recently), you buy boxes, open them, and sell the random contents. As you make more money and collect more stuff also found in the boxes, you can buy and unlock better boxes with higher value contents.
There are upgrades which do things like improve the chances of rarer items, or allow you to open boxes with fewer clicks, or, well you know – the usual sort of things you’d expect in a numbers go up game. Higher and higher numbers which generate even higher and higher numbers.

There’s nothing special about Unboxathon, and it didn’t really have the hook that some clickers (like Gambler’s Table or Timber Rush) seems to have, but it’s OK to kill some time, I suppose.