We can list various things to consider here, unless it's best somewhere else?

Physics

• Gridmaps in godot have issues with KinematicBodies when using Bullet Physics. If Gridmaps are used, make sure to switch to GodotPhysics in project settings, to avoid this issue (unless it has been fixed).
  godotengine/godot#61616
• If using Bullet physics, move_and_slide() causes jittering when moving against walls. To solve this issue: "Create a function that wraps is_on_floor() and returns true if is_on_floor() returned true at least once in the last 3 physics frames (or 2, but it may not always suffice)."
  godotengine/godot#32182

Raycasts

• intersect_ray appears to act differently when using GodotPhysics versus Bullet Physics. It seems less accurate using GodotPhysics, so we may need to document what exactly, if there's anything noticeable. One thing I noticed is that intersect_ray fails to collide with a BoxShape if one of the extents is under 0.5
  godotengine/godot#49055

Animated Sprites

• If AnimatedSprite3D is used, there can't be any modifications to the shader, since this isn't yet supported in Godot. So you can't apply any cool effects to billboarded sprites, unless we build our own animation system (I'd rather leverage whatever godot already has).
  godotengine/godot-proposals#4607
  godotengine/godot-proposals#3266

GLTF Imports

• If gltf files have embedded textures, Godot won't apply the correct filter setting to them.
  godotengine/godot#45206

Editing the settings for embedded textures is a bit confusing for beginners due to how they are buried in the Inspector. Here are some steps for accessing it. (Note: you'll have to create an inherited scene in order to access the properties within the gltf (you can't directly edit them as far as I know, but I could be wrong) ).

• Users might think that they have to go to the Material setting of the MeshInstance, however, they need to click the Mesh instead.
  
• This will reveal the Surfaces that the Mesh has, each surface has a Material that can be edited.
  
• Open the Albedo setting and click the Texture.
  
• Then open the Flags for the Texture and disable the Filter setting. You can also edit other settings in the Material if you like.
  

GLTF Imports part 2 (no code involved, just Godot's UI)

You can work around blurred textures by instancing your gltf file to a inherited scene, then going into that scenes material properties (inspector tab) and change the filter setting of your material. If your are having problems to make your model emmit it's own light, it's in the same configurations. The only problem with this workaround is that if you change the model you have to go trough this process again, creating another scene.

Visible seams along edges of tiles

• (add more info)
• Seams can be due to pixels that bleed across the UVs. See this page for info: http://www.crocotile3d.com/guide/waterfall/waterfall.html#anchorbleedingpixels
• Seams can be due to imprecise vertices that aren't aligned exactly ontop of each other. You can select them in Crocotile and press the O key to round them to the nearest pixel.

1. Base Godot Project (from legacy)

• basic 1st person mechanics with 2D characters in a 3D environment.
• basic AI for NPCs.
• basic collisions.
• basic 3D camera.

2. FPS (project 1)

• 1st person interactions with 2D characters and 3D environment.
• Agressive AI for NPCs.
• Character game states.
• NPCs game states.