Hopoo Games gave the world its first good look at their upcoming game last spring in a post over at the studio’s development blog. Surprisingly, the sequel broke with the original Risk of Rain’s 2D side-scrolling layout and the developers have explained why in a recent interview.

Speaking at length with PC Gamer, Paul Morse and Duncan Drummond said Risk of Rain 2 didn’t start out as a 3D project. “We had a 2D prototype,” said Drummond. “The twist for that one was you played as the monsters in the previous game. We didn’t want to make Risk of Rain but again.”

One of the things they wanted to do with this new project was show items on the player’s character. It was hard to properly show this in 2D, so they started looking at different options for meeting this requirement. “One week it was 2D, the next it was 2.5, and the next week it was 3D,” said Morse. “And we were pretty much making the assets in 3D and showing them as a 2D thing, so it was kind of a waste. Once we transitioned to 3D, it was like, ‘OK, we can actually do this if we want to.’ That’s where it took off.”

The original Risk of Rain as a a Metroidvania-style action platformer with a few roguelike elements. Namely, players controlled the survivor of a spaceship crash in a futuristic world where levels include procedurally-generated elements. Out in 2013 on PC and then 2016 on PS4 and Vita, it’s one of the more underrated shoot em’ ups, both in terms of the interesting items and exploration as well as the extreme difficulty. What we’ve seen of Risk of Rain 2 so far makes it look like a pretty faithful expansion of the original game; one that translates the frenetic pixel animations of the first into lofi but snappy 3D action.

It’s clear though that trying to translate a side-scrolling game into three dimensions has given the developers a lot to think about. “In 2D it’s pretty simple to go from a prototype of a level to making the tiles and putting them together and creating assets,” said Morse. “But in 3D, it feels like you have one shot once you get into designing the level. And then prototyping in 3D is much more difficult. Do you use Lego? Do you use clay? Do you use other programs like SketchUp? Do you fully make this world in detail and then just make it again? That’s been one of our harder points than a 2D version.”

All-in-all this has meant slower turn around times and more deliberation on the backed before design concepts are selected to get the time invested in them that’s required to see examples running in the game. Hopoo Games consists of a very small, lean team, which is part of why the studio has been so slow to share what they’ve been up to on the game. Simply put, it’s a lot more involved than the original Risk of Rain and so ramping up has been slow going.

They went on to mention some of the new enemies and abilities players will encounter in Risk of Rain 2 and that while it’s taking on a bigger, more sprawling world, it will still favor the environmental storytelling style of the first game. There’s a possibility the game could come out next year but the developers aren’t committing to anything at this point and it seems safe to assume Risk of Rain 2 won’t get a proper release until sometime in 2019.