There should be a UI scale option in the settings, but the values you can set it to will really depend on your specific device. Can you let me know your device model?
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I can understand why you’d want to try Shattered on a retro handheld like that, but unfortunately it will be pretty heavily limited by that resolution. On landscape mobile devices Shattered runs at an internal resolution of 240x160, which can only be zoomed 2x on your device (to 480x320), that will make the UI look quite small. There won’t be a setting to change this, as 2x is the lowest the UI scale level can go.