Symbiont

Web version is slightly different from downloadable game.
Settings and hi-scores won't be saved across sessions, the game is kept at an x2 scale and there are some superficial in-game differences that shouldn't, however, change the feel of the game noticeably.
If you'd like a definitive version of Symbiont, play the downloadable version!

Action-platformer/horizontal shoot-em-up hybrid originally made for GBJAM 9.
Use your extending tentacle attack to get through the underground section, then soar through the space tunnel and destroy your enemies.

The game consists of two levels:
Level 1 is played in a run-and-gun style, similar to games like Mega Man. Here you must navigate an open-ended level, defeat or avoid enemies along the way, and use your tentacle ability to pull levers that open doors.
Level 2 is played in a horizontal shoot-em-up style, similar to R-Type. You can use your charge shot to defeat beefier enemies, and don't miss out on the shield power-up that certain types of enemies drop. It'll come in handy during the later sections of the level.

The game has a sharp focus on challenge and level layout memorization, similar to old-school games like Battletoads or Ghosts 'n Goblins.
Reach the highest score possible by learning the workings of each level and using your knowledge to manufacture a perfect run. Big score bonuses are provided for beating the level without dying and for killing every enemy on the level. In addition, beating the level boss without killing any of the enemies prior to that on your first try will provide and even larger bonus.

Game graphics made by YoukaiDrawing.

CONTROLS
The game's controls mimic Game Boy's control scheme. Here's how it works on the keyboard:

Z key: B button (shooting, also used for a tentacle attack in platformer mode)
X key: A button (jumping, used for charging your shot in shoot-em-up mode)
Arrow keys: D-Pad
Enter: Start button (puts the game on pause during gameplay)

Level-specific control inputs:
Level 1: Press Down+B for the tentacle attack. Press Up+B to shoot the tentacle upwards (useful for pulling levers and defeating some types of enemies.
Level 2: Hold B to charge energy for a powerful attack. Hold A for autofire: this allows you to shoot your normal bullets at a constant rate, but not as fast as possible by tapping the B button.

The game supports XInput gamepads as well.
Keep in mind that gamepad controls also stick to the Gameboy's control layout, so the A button would be the right button and the B button would be the bottom one.