Message for people thinking they would release some GameMaker HTML5 game at some point...
My GameMaker game (wich I thought wasn't that costly) has been running like shit when converted to HTML5. I think it's GML converted to Java and damn, it's painfully slow it seems.
I had to start some drastic optimisation even just to be able to run my test room at a satisfying framerate. I changed the way I was doing some conditions so the engine is drawning less collision rectangles, I scrapped my parallaxed backgrounds for a fixed one, removed draw events for sprites, and remove a little "move contact solid" I was doing in certain situations in order to fix and admittedly rare bug.
Right now I am running my room between at 60fps with hiccups (some stuttering). It still is quite alarming because I can't imagine the thing when I will have NPCs in there + sound, etc. Even worse, my game is a Metroidvania platformer so the environnement will be semi-open and quite huge. I am a bit discouraged and I wonder if having a 60fps HTML5 game without being an experimented programmer is possible at all.