Who did the sound design? Just curious. The person listed for that in the description seems to be another pixel artist, and the Twitter also seems wrong.
Well, I have a mitigated opinion about the HTML5 export of GMS2, but it's mostly because of how we worked.
We have one very large scene with a lot of objects that runs at 600 FPS on PC and the first time we tried the HTML export we had a great slideshow at 5 FPS on Firefox.
So I added many hacks (mostly deactivating/activating objects that are not on screen) and we ended up having decent performances on most machines, this is what you can play now.
But those hacks cause some bugs (sometimes the entities will be activatied before the floor collider and they will fall through it).
Now, if we tested the game from start in HTML5 we could have anticipated the issue and design the level in another way. But the pricing (150$ for web export) doesn't encourage the devs to do so.
But it's still one of the best engine for 2D HTML5 games as long as you are aware of the limitation.
Completely unrelated, but I cannot play a game with any kind of skill unless I'm using a controller laid out like an old SNES gamepad.