The second demo app provides a virtual lab and has as an assignment to the learner to create a simple electric circuit.
Feedback or learners
The interaction with the virtual lab without any suitable pointing device is difficult. This might be the reason for the feedback of the smartphone users (and the tablet users as well).
Conclusion: learning apps that make use of pointing devices are only partially suitable for smartphones (and tablets). In courses using these items, learners must be informed about the problems using smartphones or tablets before the beginning of the course.