Failed games don't count
Allow teachers to be able to not count games as completed if the student loses all their lives towards their lesson completion. This would require students to pass the game the number of times I set before they pass their lesson. (this way students that are in a hurry to get to freeplay mode still have to do well on their lesson).
Adminwratke (Admin, Tonic Tutor) commented
This does seem like a good idea, and we'll take it into consideration. Our major concern is that it may potentially end up punishing students who are trying their best at difficult games like Robot by making them play it endlessly before their lesson is finished. Our goal is give as much control as we can to teachers while making the process of using Tonic Tutor for students as "frictionless" as we can so that they don't get frustrated or bored. It can be a difficult balance to achieve.
Another possibility is giving teachers the ability to set a lesson score threshold a student must reach in order to have access to Freeplay once their lesson is finished.