There are levels after the elevator part, you just need to press a button. The game reminds me of Katana Zero. But i think the person who worked on this could not finish it cuz it says "Development build" , like not the final game.
Ah gotcha, the white bar was the button. Accidentally clicked the "dash" button and shot out of the elevator at one point thinking it was it, but I was able to complete it now. Thanks!