when jumping against a ceiling, and the player is also moving along the x-axis,

the player will be snapped to a wrong x value.

By logging the tile x,y values, i found that the hero_y is checking the ceiling tiles instead of the empty tiles along the x-axis.

2 solutions exist:

• resolve hero_y first, so that hero_y cannot be inside tiles
  • move this to before line 101

    mini2DPlatformer/index.html

    Lines 143 to 154 in c7036a3

    	if(hero_vy < 0){
    	// Get the value of the tiles at the top corners of the hero
    	tile1 = map[Math.floor(hero_y)][Math.floor(hero_x)];
    	tile2 = map[Math.floor(hero_y)][Math.floor(hero_x + hero_w - .1)];
    	// If this tile is solid, put the hero on the bottom side of it and make him fall
    	if(tile1 == 1 || tile2 == 1){
    	hero_y = Math.ceil(hero_y);
    	hero_vy = 0;
    	}
    	}

    , or
• add hero_vy onto hero_y after the hero_x resolution code,
  • aka move this to after line 129

    mini2DPlatformer/index.html

    Line 77 in c7036a3

    hero_y += hero_vy;

Hi thank you for letting me use your project as a minimal platformer starter.

just a comment on the custom physics:

here, adding g to the acceleration makes the player drop at increasing acceleration, aka going cubic instead of parabola

I believe the correct way is to add g to hero_vy every frame instead. Like this:

-  hero_ay += g;
+  hero_vy += g;
   hero_vy += hero_ay;