First progress report
Thanks for dropping by my stream and help!
In an hour I had an acceptable game design - with some vague areas. It will be an action game and probably sports some rogue-like techniques.
As for the GBA dev part, I have created the World's Most Epic Worm and got it shown on the screen. This was the first thing I was afraid of. Now it's crossed out, fortunately. (Along with other toolchain question marks.)

In some hours I'll go live again. Next up is some basic background handling, and some sprite moving action. Maybe we got a boss on the screen as well. Follow me on Twitch to get notified!