Infinite Craft starts with four elements — Water, Fire, Wind and Earth — and no rules beyond dragging two things together to see what they make. Water and Fire make Steam; Steam and Earth make a Geyser; keep going and within a few dozen combinations you are making things nobody planned, because the results are generated on the fly rather than written by hand.
Neal Agarwal released it in 2024 and it spread instantly, mostly because of the 'First Discovery' badge: if nobody has ever made a particular item before, the game says so, and people started racing to invent absurd things. There is no goal and no ending, which is the point.
There is no fixed number — results are generated when two items are combined for the first time, so the space keeps expanding as people play. That is where the name comes from.
That no one has ever created that item before. The game marks it, and chasing First Discoveries is what most long-term players do.
No. It runs in the browser with nothing to install and saves your discoveries in the browser's own storage.