Spelunky 2 was announced in 2017 and showed off its first gameplay trailer in 2018, which is also when it revealed a release target of 2019. Alas, it doesn't look like that's going to happen.
Hey, Spelunky fans! Unfortunately, I don't think we're going to get to release Spelunky 2 this year. Development is still going well and we're not far off target, but the density and detail of the game is demanding more time.Thank you for your patience. pic.twitter.com/BJvsHUWAY0August 14, 2019
"Also, apologies for the lack of updates! It can be tough balancing communication and dev time (and not spoiling too much). When things are quiet, we're just working away. There will be more updates coming, but for now we're focusing on development," Yu, the designer of the original Spelunky, said in followup tweets.
Yu hinted that the extra time required could be the result of responses to the trailer. "While I still love the overall style, we've been adding more detail, as well as increasing the contrast to make existing details pop (some were pretty subtle and compression wasn't friendly to them)," he said.
"As soon as we have a release date for #Spelunky2, we'll make sure everyone knows! We can't wait to show you more, although of course the best way is for you to experience it for yourself at launch. All the crazy stuff we're adding makes me buzz with excitement. :)"
So it's still technically possible that Spelunky 2 will be out this year, insofar as Yu didn't come right out and say that it won't be, but it sure doesn't sound like it's going to happen. I think we can safely mark this one down to 2020.