1. device; contrivance; mechanism; gadget
文字が浮かび上がる仕掛けになっているな。I see, it's designed so that letters appear.
2. trick; trap; calculated manipulation; gambit
となれば、敵の仕掛けに乗るしかない。In that case, we have no choice but to play along with the enemy's trap.
3. (small) scale; half finished
4. commencement; initiation
5. set up; laying out; preparation
そもそも、仕掛けはとっくに済んでいる。The setup was finished long ago anyway.
6. challenge; attack