Merge 2048 takes the 2048 number-doubling idea and turns it into an aiming game: you shoot a numbered 3D cube at a stack of blocks, and hitting one with the same number and colour merges them into the next value up.
The red line at the bottom is the fail condition — let the stack reach it and the run is over — so you're merging against a rising tide rather than at leisure.
By chaining merges — each merge doubles the value, so getting to 2048 means a long sequence of successful combinations without letting the stack build up.
If the block stack crosses the red line at the bottom of the play area.
Yes — drag and release to shoot. Nothing to install.