I like playing games like this..... but I always get my butt handed to me...... but I like playing games like this......

Trailers are looking good. I'll wait for few gameplay reviews, but it might be my entertainment for the coming weekend.

I know how you feel.
I like shmups. I am absolutely terrible at them, but I like them.
Oh, and, I like this type of games too.

Rated M on PS5, yet you listed it as 18+.

The ESRB rating is M (= 17+).
The German USK and the European PEGI systems don't have a 17 rating. But they do have 16 and 18 ratings.
Therefore, GOG, as an European company, goes with the higher rating - the 18 rating.

It's PEGI 16.

Apparently, from the few reviews I saw it seems to have nice combat, be solid and polished from a technical standpoint , but it's pretty short (~8 hours) and could have used more variety in levels and enemy design. Still it seems rather positive overall.

It's also USK 16.
But the highest rating is the ESRB's "M" (= 17+).
And as we have already established: neither PEGI nor USK have a 17 rating.
Therefore GOG (again: as a Europeasn company) goes with the next higher rating after that: 18.
That way, they don't get in legal troubles.
What do you care anyway?
Is it age restricted for you in the US? Are you banned from buying it? I don't think so...so, where's your problem?

omfg again

GOG uses 17+ age gates often, I don't see why one couldn't be used here.
It's not nearly as big a problem here as with Shinovi Versus since this can't be easily mistaken for an eroge, but GOG is still mislabeling it.

Is not "grueling" a negative description? I am not sure I want to play anything described as grueling, seems like the oposite of fun

If they don't want legal troubles they shouldn't have eroges without age gating.

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