Yes. Sparckman already did an Undertale-Demo. youtube.com/watch?v=mt7N6W9XETo
I did a Jump ‘n’ Run Game with a Level Editor with GDev. At PC the Game runs smooth AF and the Mobile-export to!
I encountered some sound issues as well. If i remember correctly, using .ogg files instead of .mp3 works. Also, if running on html, certain browser seem to have more issues than others.
I’m not 100% certain though, so maybe others can clarify the issue