Tengai is a classic side-scrolling shoot’em’up from back in the mid ’90s. It’s now been re-released, gloriously old-school and all, free on smartphones.
It was known for being tough (for its time) and different in its choice of using characters rather than ships.
Tengai, also called Sengoku Blade: Sengoku Ace Episode II also made waves for giving players heroes with more than a basic backstory, each having their own endings. The game features characters battling their way through a fantasy version of Japan. It appears all six characters from the original game are playable here as well.