For perspective, I'd consider Rain World to be the best game I've played and close to perfection. Downpour is great but the problem is that it makes a lot of changes and I am so enamoured with the base game that most of these changes feel wrong.

Where Rain World is grounded, subtle and naturally unfair, Downpour is wacky, blatant and unnecessarily frustrating. The new slugcats have ridiculous abilities that change the player from a natural part of the world to a one-of-a-kind superhero. This is countered by the environments and creatures being tougher to deal with along with. Creatures that were seen only in the 'hard-mode' hunter class are now commonplace in every new campaign along with the previously neutral scavengers being more aggressive and powerful. New creatures are mostly stronger 'remixes' of existing creatures. The game is harder now but I don't think it's more fun or interesting. The weaknesses of the new slugcats perfectly encapsulate this feeling, with each one having restrictions on their abilities in a way that was presumably intended to aid balance or immersion but for me it just made it more frustrating. See Artificer's explosion cooldown or Saint dying of cold or Gourmand exhaustion for examples.

I was surprised and somewhat disappointed to see most of the new content being focused on adjusting existing content rather than being entirely new, a lot of the regions are places that already exist but at a different point in the timeline. The totally new regions are primarily areas that the base game already teased as being part of the world but weren't explorable. As for any new depth in the ecosystem, well I wouldn't say there was any. The changes all seem focused more on gameplay and lore rather than creating a believable world.

Downpour goes out of its way to answer any questions the player might have had while playing Rain World, but I think there's a lot of value in having these questions remain unanswered. Most of the new campaigns don't give you this option, instead giving the player some kind of primary goal; performing a task that has major implications on the story. In the base game you could entirely miss the story and still have a rich experience.

This DLC is a relatively fun experience with a huge amount of quality content. It’s extremely impressive, especially considering it started as a purely fan-made expansion. Ultimately though, I feel there is an evident lack of cohesion between the intentions of this DLC and the base game, while this is high quality ‘fan content’, it has somewhat tarnished the perfect score card of Rain World and I can’t help but have a bitter taste in my mouth when talking about it.

A great 3D action platformer, this game is extremely competent even by modern standards with fun movement, combat and exploration. It's extremely impressive to me that such a well-rounded game came out in 2002.

I have some nostalgia for this since I played the sequel and demo for this game a lot as a kid but I only got round to playing the full game for the first time a few years ago, replaying it now was surprisingly fresh but still familiar.

The visuals have certainly aged a bit but everything else is solid, the characters are fun, there is good variety in the gameplay and level design. Overall I don't really have anything to complain about besides the final boss being a big difficulty spike. If you want to experience some peak early 2000s action platforming then this series is a great choice.