They just added full control over the direction of movement for your character. A huge update. I think they must have compensated the enemy power / difficulty for this or else it would be too easy? I tried it and it's pretty hectic. I really like the control but I'm a bit torn since the original version could easily be played with 2 tap buttons. This movement adds a whole lot more coordination esp with the "bullet hell" type gameplay. This btw is one of my favorite mobile games of 2019.