Mekorama

Platform: Android, iOS, Switch 

Size: 4.7 MB

Price: Free

Mekorama is a puzzle game and it's directly inspired from the gorgeous Monument Valley. It's also free and with an infinitesimal number of user made levels, you can sink hours into this "2.5D" puzzle game. It's a beautiful looking game and not to mention, it's free. 

Robot Wants Kitty

Platform: Android, iOS 

Size: 8.9 MB 

Price: Free

Robot Wants Kitty while only having six levels follows a robot which has to collect kitten each level in order to acquire powerups. If you're a sucker for the classic Metroidvania formula and you're looking for a way to kill some time, this game's got you covered. 

Hoppenhelm 

Platform: Android 

Size: 22 MB

Price: Free

Hoppenhelm is a great pick up and play game. An endless runner with an art style similar to action platformers you would find on the SNES or Sega Genesis, Hoppenhelm oozes a lot of charm. It also has a lot more depth than other similar endless runner type deals, with its character customisation features and randomly generated levels.