They are already ripping off Hardcore

Yeah, I noticed that too. I don't even think Hardcore will be very good, but a shame to rip off something so quick. "Oh, POV for all the action scenes would be cool, it worked for this indie movie recently, lets copy that"!

The only thing different I guess is that this film can also have non-POV shots included in those action scenes so there's a little differentiation.

You're acting like Hardcore is the only action movie to have POV scenes which it's not. Heck, even Uwe Boll has done it in his movies. Hardcore is only the first movie to be entirely POV, not the first movie to actually incorporate it. Plus, Grimsby started filming on July 4th which is before the first look at Hardcore was released on the creators Youtube page a few months after in November so I think it's highly unlikely that they copied them.

The same that made Hardcore had made several music videos like for several years, and they are very popular on youtube, so of course filmmakers have seen it. Even a lot of Michael Bay's film has point of view shots from the gun like Pain and Gain, and I think I saw that in 13 Hours trailer.

Even Doom did a full POV/FPS 7 minute long scene in 2005. In that sense they are ripping off Doom. Which where reference to the video game and the FPS genre.

Peep Show have done the POV shtick for 12 years now.

how did they rip off hardcore? i fail to see it, its not like the entire movie is first person...

rip off is a bit of a strange term though in movies. I mean saying pov somehow belongs to hardcore is a slippery slope. Although it's fair to say hardcore utilised it a lot.

Now I see why it resembles Hardcore so much. Here's an excerpt from an interview with Ilya Naishuller:

Sacha Baron Cohen and Louis Leterrier invited me to shoot that sequence for them, but as much as I love SBC's comedy (been a fan of his for more than half my life) I couldn't do it due to scheduling conflicts. So instead I showed them a very early cut of some of Hardcore Henry's sequences and gave them a short list of do's and don'ts. They followed some and avoided others.

Hardcore looks unwatchable to me. But you do realize that movies have copied video games for years (not to either's credit, for the most part).