All audio is also written as text in the HUD, but it may come as a bit dry without the voiceover.
That said, I'm planning to update the game next week, once the jam is over. One of the additions will be an extra HUD element where the mission will be clearly stated, and also signs in different areas to avoid ambiguous indications. You may find it more pleasant if you play it then.
Thank you for letting me know about potential issues, I will keep in mind that some people prefer to play without sound :D.