Often on web version of the app the audio is being cut and here i have heard only "me gusta comer arroz" - marked wrong obviously... Weird thing is that it is often cut in such important places - like missing final "por favor" or "grazias".. like someone was doing it on purpose ;P
Just the way gustar works. Think of it as "rice pleases me" or "rice is pleasing to me"--conjugate gustar to go with rice/it gusta as the subject (not yo) and then the "me" for the object. If you like rice, it's the same way with you as the object--"te (not tú) gusta arroz." If you like something plural, you change the gustar conjugation: I like eggs--me gustan huevos (eggs please me).