TL;DR:
A fun idea could be to implement splits at each checkpoint in Deathrun.
It would display your time up to that point; and how much time you gained or loss in smaller text below it in. Both times would be colored red, green, or gold.
Red would be if you got to that checkpoint slower than your last play of the map. Green would be if you did it faster than last time. Gold would be if that was the fastest time you’d ever done it.
Another thing to consider is that there is a speedrun where players have infinite leaps. This could make the split system useless as all of your times would be red in public games. A way to fix this is to split it into two split systems, one for public games, and one for custom. There could also be an option to view your best splits in the PB book for each map.
There could also be phrases attached. Like if you got red, it could say in red: Pick up the pace! If you got a gold split, there could be confetti on the sides of your screen and a congratulatory phrase. Sound effects could be included as well.