I don't know if this trick is already known, but I've come across an exploit in the Time Attack mode where you can through the use of checkpoints achieve times lower than what should be possible to get through normal gameplay. It works as follows:
Reach the checkpoint marker while in Time Attack mode on any level. Then, have a monster/hazard kill you, and choose to restart from your checkpoint. The timer will now start at the same minute and second you reached the checkpoint, but it will reset you tenths and hundredths. This means if you hit the checkpoint at 1m 10.99s, restarting from the checkpoint will instead set you off at 1m 10.00s.
Depending on what your tenths and hundredths were before hitting the checkpoint, you can now achieve a potential 0.99 second time cut, minus the time it takes for Bloo Kid to accelerate from 0 to full speed when starting a level.
For example, I've been able to cut the time on stage 1-2 from a 34.21 to a 33.76 using this method, as can be seen here:
