This is a nice game! The character-switching mechanic works well and the level design is pretty good. Unfortunately the jumps are a bit too tight (over spikes, and up on to ledges), which became very frustrating due to needing to be pixel-perfect. Getting stuck on the buttons was a bit annoying too. But I still managed to get through quite a few levels (not sure what level number I got up to, maybe 7 or so). The visuals and music are nice too. Good work!
PS: Thanks for the Linux build.