Cosmo's Cosmic Adventure

Cosmo's Cosmic Adventure is an EGA platformer game for MS-DOS written by Apogee Software.

The eponymous alien's family is forced into an emergency landing on a planet and when Cosmo is away from the ship, his parents are kidnapped. When the player is given control, it's up to him to find Cosmo's parents over the course of three episodes.

An interesting technical note about the game is that while it supports Adlib-compatible sound cards for music, it provides sound effects only through the PC Speaker.

Tropes used in Cosmo's Cosmic Adventure include:

Bottomless Pits: Usually played straight. Subverted in episode 2, level 1, which eventually leads to a giant monster thing
Satiating Sandwich: Two per game, each one giving you an additional hit point.
Exposed Extraterrestrials: Cosmo, his parents, and presumably the rest of his race are normally naked.
The Goomba: The small red enemies, which just walk around and are defeated by a single stomp.
Goomba Stomp: The player's primary attack.
Heart Container: The hamburgers, which increase your hit point capacity by one.
Invisible Monsters: A type of robot which will shove you around.
The Lost Woods: There are a few levels set in forests, but the fourth level of episode 1 best exemplifies this trope, with its creepy-looking trees (with eyes looking out of them), ghosts, and a thunderstorm.
Parents in Distress: The reason for the adventure.
Shareware
Shout-Out: The default high scores listing is names of characters from The Simpsons.
Spikes of Doom: Some are stationary, while others continually retract into the walls and then come out again. They can usually be removed with bombs.
Stalactite Spite: Applies to some of the short yellow spikes.
Stuff Blowing Up: The player's other attack.
Stupidity Is the Only Option: The first level of episode 2 is just a giant gradually narrowing pit which leads to a giant monster. The first level of episode 3 takes it farther, which requires you to walk straight into a monster's mouth to continue to the next level
Tube Travel: Via the green pipes, which, oddly, look too thin for Cosmo to fit.
Unwinnable By Mistake: Some levels contain a Mook Maker plant that will swallow the player and spit him out again. If you bomb it while you're inside, you're stuck and will have to load a saved game.
Wall Crawl / Wall Jump: Using Cosmo's suction hands, you can repeatedly jump and stick to walls to scale them. You slide down ice walls, but it's still possible to get up them.
Womb Level: Mentioned above.