-a tournament mode where each player gets to run each level a set number times and it adds up each player's scores. we do this ourselves manually but it would be cool for the game to keep track.
-play with yoshis when 2 or 3 people are chasing instead of having it only in 1 vs. 1 mode.
-play the small course even when 3 or 4 people are chasing.
-different time limits.
-turn start on/off
on another note, if you want to have a crazy fun time with this game, play 4 vs. 4. choose up teams however you want, but picking playing cards is the fairest way to go. just have an A, 2, 3, and 4 in both black and red. have everyone pick one. blacks are on one team and reds are on the other. choose before drawing which team will run first. the team that goes first has their "A" player run while the entire other team chases. next the "2" player runs, then "3", and then "4". then the team that was chasing takes their turn running away one at a time. total up all of the times to see which team wins. for a longer game, have all 8 players get one run on each course. the totals would then have 12 runs per team.
after the match, mix up teams and play again! you can do this for hours without getting bored with it. if you have competitive people playing, it will be intense. if you want stats, keep track of match wins and losses per player (entire winning team gets a win, entire losing team gets a loss), tackles, average run time per player, and perfect runs.