Alright, went through the game as Jelly Tails with one goal: Go fast! (Stopped at the Metal Sonic fight because I felt that would play the same.) Some more thoughts:
The bounce(stomp) is WAY more absurd than I have given it credit for. Find a slope, bounce, and watch as Jelly Tails suddenly gains ALL the speed. The steeper, the better! Go straight into flight and watch the level zip past! ACZ1 is a good level for this.
Dashmode as it is now tends to be... sporadically used. I don't think I really use it in ACZ1 at all, mostly abuse slopes and fly past everything super fast. In places I feel inclined to stay on the ground (RVZ, some of DSZ2) it speeds up Jelly Tails a lot... because it's dashmode, of course it does. But it wasn't something I feel I really benefited from for most of the game. Jelly Tails goes super fast even without it, though.
I think the only level that took me longer than two minutes was Egg Rock act 2. I got a time of 2:18 there, if I recall. Most levels didn't even take a minute... though I'm using ingame timer as a reference, and not counting time spent dying and restarting to rid myself of slow starts.
Maybe Jelly Tails could start another stomp after hitting an enemy? Like how it works with the bubble shield?
Speaking of shields, tried that after my speed playthrough. Every shield placed with objectplace, then some messing around. Honestly, I expected the shields to not do anything, I don't think the stomp and the shields are both supposed to activate at the same time, but they do, and I tried them anyway. Some shields did basically nothing (lightning, force). The others? Varies.
Elemental removes all your forward momentum instead of just the majority, and places fires when you bounce. Eh.
Fire is great, it counteracts the typical speed loss from starting a stomp.
Water is interesting. You can only use the jelly-stomp after re-spinning from flying. Otherwise it's vanilla Bubble bounce all the way.
Whirlwind, my favorite wind shield, is also interesting. You tend to alternate between the whirlwind jump and the bouncy-stomp. The whirlwind jump limits your upward momentum. This gives you WAY more control than ever over your verticality, WAY faster.
And the Attraction shield just does homing when near enemies, standard.
I didn't think I'd have so much more to type. Should Jelly Tails have the shield abilities activate?
I am aware of the transparency issue, and will hotfix it as soon as possible.
Also yeah, do jt_spikeinv in console to give it a try.
Ah, thanks! Just gave it a try. Yeah, it doesn't work with sideways spikes either. CE2 has quite a few of them and... yeah. Seeing it in action gave me Gooigi vibes! Not sure why it's off by default.