RetroAchievements for Terraria require tModLoader, which you normally can’t run on Android. I tried getting it to work with GameNative, but had no success.
But recently, I discovered this Android app that lets you run desktop .NET apps: https://github.com/FireworkSky/RotatingartLauncher
The installation is pretty straightforward: you just specify the path to the GOG Linux version of Terraria and the path to a ZIP file containing tModLoader.
For mods, I downloaded them on my PC through Steam and simply copied the .tmod files to:
<Internal storage>/RALauncher/Terraria/tModLoader/Mods
For save files, I set up Syncthing to sync ~/.local/share/Terraria/tModLoader/ to: <Internal storage>/RALauncher/Terraria/tModLoader
By default, the game opens stretched at a much lower resolution, but going to Settings -> Video -> Fullscreen automatically sets the correct resolution.
To log in to RetroAchievements, I had to connect a keyboard to enter my username and password. While doing so, I noticed a small bug: connecting a keyboard while the game is running crashes it.
I haven’t seen this app mentioned on Lemmy, so I hope someone finds this useful.
P.S. The handheld in the picture is an AYN Thor.
It’s nice to have some guides pinned and to keep notes. Some games have had second screen mods but a number of them are vibe coded and some of these devs broke open source licenses doing it so I’m steering clear of those.
Wii U is another platform that benefits from it as the bottom screen acts as the Wii U tablet controller though I’ve not yet tried it out personally.
As a Wii U owner there are very few games that actually utilize the bottom screen for more than just displaying a minimap or your inventory