I was totally thinking the same thing! I used to play tetris so much as a kid, also had tournaments but against family members. Lol.
I think the thing that makes it so hard is you can't rotate the cursor. It messes with me sometimes. When I started playing it, I got stuck in story mode fighting off Isabelle but I took a break and came back later then beat her. Then went off to finish the whole thing.
I guess the only tip I have is that it really helps if you can find a combo anywhere fast. Keep checking the bottom areas and maybe do a sort of squint if needed (lol). It gets better, don't worry. Oh and don't forget to use the power move like me. xD