The Lost City is an untimed match-three: mystical stages, gem-breaking, and boosters created by matching more than three at once — with no clock, so the only constraint is the move limit.
Removing the timer changes the game meaningfully. You can actually plan cascades rather than taking the first match you spot, which is where match-three gets interesting.
No — the levels are limited by moves rather than a clock, so you can plan each one properly.
By matching more than three crystals at once. Combining two boosters clears far more of the board than using either alone.
Yes — drag to swap. Nothing to install.