![](/static/253f0d9b/assets/icons/icon-96x96.png)
![](https://lemmy.ml/pictrs/image/S2qEBSQ4Kr.png)
You could do open source engine, proprietary assets. Like the original doom 1, 2, and 3. You can get the engine for free, but have to pay for the art assets.
https://en.m.wikipedia.org/wiki/List_of_open-source_video_games#Open-source_games_with_non-free_data
I just use termux + the simple http server built into python