I just updated the game to include an on-screen control overlay, just on the first stage.
I do, however, recommend checking the tutorial (a short one, I know everyone hates them) from the main menu to get some tips on the game.
Source: Steam Community (opens in a new tab)
Build and release context
Steam update times within 24 hours of this post. Matching dates do not confirm which build it describes.
Build 3152545 · public branch
Steam updated · First observed