I wanted to do this game as a speedrun but when I checked on platforms it was 3DS and I only have a 2DS so should I just buy a 3DS or can I speedrun on my 2DS

2DS isn’t a platform on this site because it’s just a part of the 3DS family. For any game, you can run on 2DS and select 3DS.

Ok thanks

The 2DS has the same hardware as the original 3DS/3DS XL (no new3DS), so you would categorise your runs on there. Otherwise there are no differences.