(high priority):

1. Sometimes the Critical Exponent Log Plot stops taking data (even when the randomness parameter is less than the specified critical randomness).  This bug has not been solved, and the workaround is currently to restart the tutorial (or ignore the problem and move on).

(low priority):

2. Sometimes the "Next" button shows over the "Next Unit" button on the last page of unit 1.

3. Skipping to a unit (by keypress) then moving to previous page will fail.

4. Traversal by keypress is not completely tested, may cause troubles.