Metro Exodus is not being sold on Steam at the moment due to the exclusivity deal between Epic and Deep Silver but all the controversy surrounding the switch produced something rather odd - positive review bombing of Metro Exodus on Steam.
Epic Games and Deep Silver caused major controversy with their deal to switch Metro Exodus' status from being available on Steam to being exclusive to Epic Store. This prompted enraged fans to review bomb previous Metro games, which hinted at the possibility of the same fans review bombing Metro Exodus once user reviews became available.
What happened was entirely opposite of the expectations. Fans started showering Metro Exodus with positive reviews on Steam, but many of these positive reviews carried not-so-positive messages, clearly stating they hate the exclusivity deal as well as Epic Games and Deep Silver for pushing it.
For example, the top review at the time of writing was a positive one for Metro Exodus but negative for Epic Store, which mirrors many other users' feelings which can be easily checked on Metro Exodus' Steam page. Meanwhile, others opted to put a "not recommended" tick on the game as the game updates were late to Steam users and Epic Store got the preferential treatment.
The whole situation proved to be interesting as it not only produced reverse-review-bombing of sorts, but also because this was a rare instance of pre-orders benefitting the users. Did we just say that? Ew. Be that as it may, those who pre-ordered Metro Exodus got to play it on their preferred platform, while the wary customers lost that choice.
Still, this is an anomaly and pre-orders are bad practice for the consumers in the vast majority of cases. We always recommend players to stay away from them, wait until reviews and gameplay videos kick in and then decide whether a game is worth their time and money.