Guys when your player has no idea what to do in the tutorial, that's never a good sign.
In the first minute, an NPC tells me to warm up, and he tells me where, but I have no idea what the word he says means, it's some Asian-sounding gibberish. Now I understand if you don't like hand-holding in games, but the in-game map does not work at the time, there are literally no markers, nothing marked with the word the NPC was using.
It's literally the first minute of the game, and I have no idea what to do. The room is dark AF, the doors leading out is closed.

Well... I can't figure out what you talking about either. Please, be more specific.
Do you have troubles with prologue?

My character talked to another character, and that other character said some asian-sounding gibberish word, saying I should use that before we train with him, or something like that.
Now I don't know what to do.
I don't want to refund the game, because I like the basic idea behind it, but I have no idea what to do.

What another character, Crabmaster?
When you enter the room, there is a locker on your left. Open it, take weapon (and all other things), equip, hit target (he call it "makiwara") with quick and with heavy blow. Now you are ready to train.
https://en.wikipedia.org/wiki/Makiwara

And pay attention, man. ^^ There is a lot more hard to notice things ahead. Good luck!

I think it's the main character. I'm in the very beginning of the game.
Well, this is a serious oversight in terms of game-mechanics than. Thank you for warning me, I'm going to refund and watch the game on YouTube. The game is unplayable for me this way.
[edit] So the guy in the room tells me I have to do something with a thing called 'makiwara'.
But WTF is that? WTF am I expected to do, and more important, why do I have to write in the forums of the game literally FIVE minutes after starting the game?

Nah... You suppose to find a locker first (it much closer then Crabmaster after all), then all going smooth. With all my playthrough I completely miss "makiwara" thing. Do you feel safe to speak with someone armed inside your house? I try to find everything I can, and arm myself first. ;)
BTW Thyper is not your main character. You can play Thyper only at prologue.

I found the locker, picked up my weapon, the npc tells me to train with some japanese thing, don't know what that is, stuck in the game in the first 2 minutes.
It doesn't matter any more, I don't have time for bullshit googling and forum replies after playing the game for 2 minutes, this game is clearly not for me, I requested a refund.

Well... when you picked up your weapon, full screen pop ups (almost) tell you to equip it, and then hit the target. It probably don't repeat it self but mean it nevertheless.