In case people didn't know I just discovered (thanks to NotTommy1212 or NotDeath on Discord), that after any speed increase (i.e Corner Boost) if you Slide you will keep that speed for the entire Slide. Now the Slide eventually stops and goes to 300 u/s, but if you Jump before it ends and Slide in the air, you will land with the same speed as you had before, so you can keep the speed as long as you chain Slide > Jumps > Slides ...
Note: This is as long as you don't turn too sharply or you will obviously lose all your gained speed.
See my 0-1 run for how it looks like:
With the newly added Hard Mode, which features 10 new levels I have added them to the Leaderboard. I also made a new Full-game category that adds the Base Levels + Hard Mode, give it a shot if you think you can handle it!
Link to Patch Notes:
