NXEngine Evo is a complete open-source clone/rewrite of the masterpiece
jump-and-run platformer Doukutsu Monogatari (also known as Cave Story) created by Studio Pixel (https://studiopixel.jp/).
NXEngine Evo is an upgraded/refactored version of NXEngine by Caitlin Shaw (http://nxengine.sourceforge.net).
Arrow keys to move
A Select previous weapon
S Select next weapon
W Map (only available after you've obtained the item in-game)
The default controls can be easily changed under Options : Controls. Joysticks are also supported (you should only need to change the controls in the options menu).