(kind of an expansion on the difficulty post)
i was actually thinking about this a couple days ago, after reading @ctmatthews post on "onion games" or "games that are bigger on the inside" here. she talks about getting a bit annoyed when a game reveals that it's so full of much bigger puzzles & mysteries that it becomes a different game than what you expected going in. extremely reasonable!
(i'm also reminded of old RPG Maker horror games that did their best to hide the horror/slasher/etc. elements from the game's promotion, which i think people have mostly stopped doing)
it's a tough question! communication is obviously important, but often a big part of any media, especially games and especially onion games, is hiding your hand a little bit. i think it's okay to an extent - you don't know where a book is going to end from its title or genre alone, and i don't think that's a requirement for games, necessarily...
that said, you will annoy people if you mislead them too much. i do think it's up to the promotional material, the trailer, the pull quotes, to at least imply that a game is going to have more going on than just what is blatantly, mechanically shown.
i actually think
well known onion game from 2023
VOID STRANGERdoes a very good job communicating this. the trailer is rife with a lot of things that look and feel mysterious. the basic mechanical "shape" of the game is made clear... but there is so much more going on. the trailer has so much: a barrage of huge narrative visuals (demon war, cryptic murals, frozen corpses, tons of characters), unexplained mechanics (mystery item, literally an rpg battle), "glitch" scene transitions, and a non-sequitur cutscene at the end. every part of it implies something greater than just "moving on a grid". the steam page says the word "mystery" like 3 or 4 times... it was enough for me to pick up on "ah, there's something bigger at stake".
maybe that's not the case for everyone! communicating is hard, which i guess is my point here, haha. i think it's a tricky balance to strike - not annoying your players by surprising them with a different game, but without peeling the onion right in front of them.

