Among the very best

"Go to Gold" and "Go to Gold 2" are among the best puzzle games all around, not only on iOS.
Both games tick all the right boxes:
No timer, no counter, unlimited Undo. Polished presentation and most importantly: genius level design.
There is not a single badly designed level, each has been meticulously designed with a clear goal in mind: challenge the player by making him think.
I really hope the two-men dev team (Timur and Danil) are already working on part 3 of the series.

Geri263 about Go To Gold 2 - Chinese Puzzle, v1.1.20