try to make it have a more linear flow, in other words, make the flow more defined, try adding vertical tiles for wall jumping. I just think this race is too non-linear. hope I helped : )

I already had credit enough with your fun DDA. I forgot to mention that I love the description :P.

Races always has those extremely perfect flow.
Notice the following places in your map.

-The start is good enough but you can make it look cooler if you use c-snap and place N in the wall. Not the whole N, a little part ofc., same as with the thwumps at Jim DDA.
-Improve the flow. I know it was impossible to do here but take the space there is and use flowy tiles.
-After hitting the first switch you fall down right? Or I am blind. =). At your square of lock doors. Place a one way pad there to, so you don't have any problems entering the lower department.
-With the #3 tiles there is a big change of falling of them. Not bad but you Could improve.
-Make your entrance to the last tunnel a little bit easier. It is possible but really hard to pull of correctly in one time.
-And ofc. A race must be long and have some enemies. Not to much, that will cause lagg.
-I always love the time limit. It adds some excitement.

Maybe look at the race maps of yungerkid and Riobe. The make awesome race maps. Yungerkid makes the best race tiles and Riobe just has this special atmosphere.
If you can make those kind of maps you should be giving me tips next time so your maps don't need to be like tho at all.

And this is such a long post I better shut my mouth now. =D

Good luck!