It is possible to create more complex, multi-ubit gates, including those that accept external parameters. A more comprehensive list of gates can be found, among others, at: https://en.wikipedia.org/wiki/Quantum_logic_gate or is described in the qiskit library study guide: https://qiskit.org/textbook/preface.html, and in the documentation: https://qiskit.org/documentation/ Some of them will be used in the following tutorials.
It is possible to reproduce the circuit with a bomb for more qiskits. Each time the probability of a photon passing through a permeable plate is given by the rotation gate Rx(πn)Rx(πn). In addition, a Hadamard gate has been introduced on the first qubit, acting as a random generator as to whether the bomb is in the system or not.
Check how the probabilities of detecting a bomb behave, as the number of cubits increases.