Additionally, I'm a little worried about the control group part. I expect it's relatively easy to recruit people to play a game and have them be motivated to play it, but if I tell people that "oh, but you may be randomly assigned to the control condition where you're given more traditional math instruction instead", I expect that that will drop participation. And even the people who do show up regardless may not be particularly motivated to actually work on the problems if they do get assigned to the control condition, especially given that I'm hoping to also educate people who'd usually avoid maths. How insane would it be to just not have a control group?