Frontier’s Planet Coaster won’t be released until the end of the year, but it launch its first alpha build on March 22, 2016.
The alpha version is very limited in scope, and a pretty rough around the edges, but it gives you an idea of how the game will play.
To gain access to Planet Coaster alpha build you will have to purchase the Early Bird version of the game.
This is one of the three stages Frontier has planned for the game. The first alpha version will focus on Modular building and paths. The roller coaster creation feature has been hidden due to it not nearly being complete, however Frontier did add a way to unlock this feature.
“To access coaster building, open a map and select the ‘Rides’, ‘Scenery’ or ‘Buildings’ tab, then select the ‘Search’ option (a magnifying glass) and enter the code ‘underconstruction’ (all one word in lower case) to enable the coaster construction tab.”