Firstly I think armory3d could have been THE game engine if it wasn’t so filled with bugs to the point it’s actually unusable, for two weeks now I’ve been trying to use this “blender addon” but I just can’t get it to work, for you to call it a blender game engine it should at list work with the blender we already know, but instead it doesn’t, basic materials that render fine in blender eevee and cycles will cause error in armory3d, the funny thing is sometimes the errors you are trying to fix will all of a sudden dissappear and everything will work fine until it reappear again and this makes error impossible to fix, one of the reasons I picked armory 3rd was because it could export to web, something upbge can’t do, but in upbge textures aren’t a problem and it just works overall for real I’ve not seen any major issue with upgbe because it does what it says it could do, armory3d on the other hand is just disappointing, I can’t tell you how much I’ve tried for this addon to work, it’s either you get a black or white screen error or you get some errors that just become annoying because it worked before, I’m someone who is good at learning and finding infos online about software and I could tell you that people who use this engine really don’t make games, they just get excited after being able to move the default cube with a button click, my major problem with the engine is that I don’t really know how the texture and materials work because when I add a model to my scene and play the game it gives all sorts of errors about not being compatible with the texture but then I remove all materials from model and run the game and I still get errors or just a black or white screen that displays nothing, sometimes it errors about the rig, animation action, camera positioning and so on, I’ve done research on how to solve this issues but I’ve not been successful, by the way I’ve been animating for over 7 year now and use all major 3d software so I’m already used to the default way this software works, that’s why I was looking for a game engine for blender so it’s super fast for me to learn but armory3d isn’t it.
It’s true that a lot of nodes are not currently supported, and some which are supported are not completely implemented. For a list of material nodes that should theoretically be functional check out this page: armory_docs/remarks/supported_nodes.md at main · armory3d/armory_docs · GitHub
Unticking “Cache Build” In the Flags section under Armory Project may mitigate some of these issues, depending on what the error is. Before I started doing that I was constantly bewildered why builds would seem to not play properly until I exited out and hit the play button a second time.
As for the black or white screen errors I haven’t run into that issue. I’m far from an expert, but more information on your specific issue may help someone who is more familiar with Armory3d.
The issue this addon has is far more than the whole worlds problems, after I strip all my characters of the original materials and added just flat colors and rigged the characters again because the default rigify ik rig keeps producing errors, I then decided to make game, starting with a simple walk cycle using animation action from button click, when I run the game all of a sudden my character will deform in the most deformed way possible with no errors being logged, I search online and only saw one post about it but the given solution isn’t user friendly and I’m sure will not work or still produce even more errors. If I has one wish I’ll wish for this engine to work right 
Don’t “rig”(NO CONTROLS) the character for it to work in armory, don’t put CONTROLS just import the characters and animation already done.https://www.youtube.com/watch?v=-byWaW7hl2k