u/kame-chan

Since I managed to get the highest score in Round 4 of this event, I’ll jot down the key points here.

Increase Hyper Hopper, Lowdown Beat, and Slo-Mo Beat (as evenly as possible)
Illuminoid Demolisher too. (An invincible enemy in bright places)
There's a “Staring Down” on the 1202 floor, so be sure to pick it up early on.
Get the Slow Motion upgrade early on, and use the Snake ability to apply Slow Motion constantly
To always be a snake, wear clothes with snake-like extensions and an emerald tie to boost your adrenaline.

Round 4 isn't that difficult, but I'm not sure if Round 3 is doable. I'm not sure if “Lowdown Beat” is effective against the snake's diving punch.

Here's a video.