Been playing this, it's pretty fun. The gore and weapon customisation is quite impressive, worth playing just to check those out. Also as far as I know you can't buy weapons or anything gamechanging with real life money, you can only buy cosmetics like clothes with it. You can buy shit like xp boosters, but honestly who would do that? I've only got 6 hours played and I've unlocked most the stuff I wanted, I wouldn't say it was pay to play.
You're right. My bad. I didn't pay enough attention and got the upgrade points mixed up with the in-game currency, SpaceBux.
I prefer to play the game and earn my points, currency, upgrades or whatever. It has a much more worthwhile affect.