A slow paced Metroidvania'ish (it's kinda' like a Metroidvania) / shooter / platformer / survival game. A few hidden areas / short cuts, two endings (kill last boss / escape), the usual tropes.
There is a hidden option on the main menu (the menu accessed via the title screen) where you can reset the game / clear your save (game auto saves) by hitting Esc key.
Also has control pad support (for buttons check options page).
Tip* HOLD the shoot button to shoot (you can walk back whilst aiming in the opposite direction whilst shooting).
Once you unlock the double jump note that it is pressure sensitive (the longer you hold jump the second time, the higher you go).