Since students are alternating turns, they're both getting the practice/review. Their "team" will naturally progress/break records, regardless of their starting place or individual speed. Because they are a team, they are aiming to beat their last record. I think the record-breaking incentive is more for student motivation than for assessment/placement purposes. (Personally--I wouldn't pair two students who have significantly different ability levels--more than one grade level. Just curious...have your students, or do you anticipate them asking questions about their level/records? Or did you want to find a way to use this game as assessment?)