The game doesn't prompt input commands and you get stuck in limbo since the training stage.
Also tried to contact both developers AND publisher, no response ever in months.
Absolutely irresponsible to dump the game on the store in such a state.
I hope either the devs/publisher fix this (most preferred solution) or gog themselves issue refunds, because this game just doesn't work !
Game is fixed or it wasn't really broken in first place. When tutorial asks you to "be faster" during training stage you have to press "change weapon" button - it's Y on Xbox controller, not sure about keyboard.
Sure, it was bit unobvious, but other than that I haven't found any problems with the game. It's fast, bit chaotic, with energetic synthwave music and crazy levels. Gameplay is just oldschool arcade game made in modern audio-visual style. It costed me around 0,8€ during sales and for this price - it's fully recommended!