Pixel Game Maker Series: STEOS - Sorrow Song of Bounty Hunter

This game looks like a side-scrolling shooting game at first glance, but the main character is not a fighter, but a bipedal cannon.
It's a high-difficulty action game with a screen doesn't even scroll.
The distant future when AI has taken over civilization. Suddenly AI divided into Migma and Apeiron armies and started war. You are a human hired by the Migma army with the expectation that you are indeterminate element that will bring victory.
With only two weapons - a only horizontally and at 45 degrees bullet, and a spanking bullet that a very narrow range - you board the bipedal cannon Steos and embark on a fierce battlefield of AI.

[Quickly Retry]
You may find yourself wreck many times in a battle against a formidable AI.
But don't worry. You can press the start button (keyboard: R) to retry stage immediately.
Dozens and dozens of times, you can restart and go to the battlefield.

[Salary]
You are participating in battle between AI as a hired.
So, if you win, of course you will get an allowance.
Bonuses are awarded for killing the enemy before operation end, bringing back power cells, and killing the enemy without wasting bullets.
But the best part is the scrap collection that comes out when you destroy an enemy aircraft. This is what the Migma Army is willing to pay for.
In addition, press the R button (keyboard: SHIFT) to activate the gadget “Getter”. You can use this special device to attract scrap from the surrounding for collection.
It's a deadly job, so let's get paid well.
Scrap comes when you destroy aircraft, even if you destroy your friends... Oops, I think someone is coming.

[All 50 stages]
There are 50 stages in total, spanning five locations: cities, ruins, asteroid belt, factories, and enemy headquarters.
Gimmicks of the field such as warp devices, meteorites, spinning lasers and moving floors will torment you.
You may come to mind at second half, but don't let your heart break for the Migma Army victory.

[Hidden Mode]
After completing all 50 stages, you'll be faced with a shocking truth and more hell to come...

* "Visual C ++ Redistributable Package for Visual Studio 2012 Update 4" is required.

Source: Steam Store Description