Hey uh so I manage to download it on android by using joiplay and a renpai plugin, u can get them on joiplay official website. I also downloaded the windows version of adastra bc joiplay allows u to play pc games on android. It worked for me though
You have to download the APKs for joiplay and the renpai plugin (both are on the joiplay website), then download the windows zip file instead of the APK on this page, unzip the file, then in the joiplay app find the unzipped 'adastra-17-win' file, find the .exe file in that folder and select it. Then just follow the prompts on the joiplay app and you'll have the game.