Bruh, you do realize, this is a single person, making this?
4 Momths for 4 new enemies and 2 new game over scnees is alot considering this. In my personal opinion, this eveen exceeded, what i was expecting to be added
Not to mention, the developer might stop entirely, considering, the shit unity did.
Regarding your question, the paid version contains the gallery, which is visible, when you finish the game.
And in regards to the new enemies you mentioned, i was able to encounter them, they come after the spiders. If you weren't able to get to them, they are probably part of the paid version too.