Very good game
I liked your game very much. I played a lot and got 6 millions on Terminal Velocity. I would like to say some things that maybe would be nice to improve the game :)
1. There should be a hardcore mode (maybe even the Terminal Velocity itself) that doesn't have temperature cooldown. I mean, i had to play a lot (time) to get 6kk, if temperature cooldown was off, the Ranking System would be much, much more competitive. Why? Because you won't need JUST time to beat the score, you would need skill. Anybody that can survives Terminal Velocity with the combo's cooldown would be able to beat any score, it only needs to play for HOURS (like me, lol, i did 90x combo). That would be a lot more challenging, and probably wouldn't make the game endless.
2. Players should lose points (something significant) when press press the wrong arrow, spam them or closes the whole with space bar to avoid elemental particles. Sometimes when i got lost with the arrows, i spammed them to get rid of the particles and get less damage.
Some other sugesstions to make it harder:
1. Every little round has 12 particles, at the same rhythm. If that number or that rhythm change everytime, it would be much harder.
2. Maybe more speed. I'm still not very good at it, but i guess it is possible to increase that.
I like it, 9/10. Keep up the good job to improve it! :)