Here is the full list of all 19 Tametsi achievements. It takes around 80-100 hours to unlock all of the achievements on Windows.
Complete the six bonus Circle puzzles
Complete every puzzle
Complete the three bonus Neon puzzles
Complete the bonus puzzle Reticle
Complete the three bonus Circuit puzzles
Complete the bonus puzzle Warp Zone
Complete the three bonus Lattice puzzles
Complete all six Combination Lock puzzles
Complete the six bonus Box puzzles
Complete all 100 puzzles from the main set
Complete all three Gridlock puzzles
Complete the main puzzle Endless Knot
Complete 75 puzzles from the main set
Complete the main puzzle Hilbert Curve
Complete the main puzzle Series of Tubes
Complete 50 puzzles from the main set
Complete the main puzzle Sunset
Complete 25 puzzles from the main set
Complete the tutorial