2015 isn't that old...
Some of my favourite h games are from 2009 or older
It wouldn't really be old if it were, say, a decent RPG with a fair amount of text - indeed, I can think of some untranslated RPGs written in VX, such as ハルウル, that I wouldn't blink twice seeing translated today. It takes time for these games to be noticed and longer still to be translated, after all.
But when it doesn't seem like the maker was really that invested in the game, and there's minimal text to explain why it took so long to be released in another language... Then it feels strange to see them again years later. I mean, I guess it isn't
that old? But it just feels odd that it wasn't either a more recent action game, or a more ambitious project - it makes it difficult to understand the translator's reasoning.