I only spent a minute on the trainer, but my recommendation is to change the user experience from "type M 5 times in a row" to something like "get to the target with a single keystroke". Without any expertise is making a Vim training program, I feel like showing someone a goal and having them think of what keystrokes gets them there will be more effective than telling them the keystroke and having them type it 5 times consecutively.
I only spent a minute on the trainer, but my recommendation is to change the user experience from "type M 5 times in a row" to something like "get to the target with a single keystroke". Without any expertise is making a Vim training program, I feel like showing someone a goal and having them think of what keystrokes gets them there will be more effective than telling them the keystroke and having them type it 5 times consecutively.