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Felix the Cat is an unauthorized port of the NES game of the same name. The developer is not credited anywhere in the game, but it's assumed it was developed by BMB, and it is known that it was published by KDS (Kudos).
Overview
The plot of Felix the Cat is explained on exactly one screen before the game starts: just like in the NES original, Kitty has been kidnapped by the Professor for a ransom, that ransom being Felix's magic bag. Having no other choice, Felix goes on an adventure to rescue his girlfriend.
Similarly to all of BMB's NES-to-MD ports, Felix the Cat features the most basic set of mechanics, enough to resemble Hudson Soft's version. Likewise, this game has no bosses at all, contains only a handful of levels from the original (in this case, 12) and includes the same playlist with songs of different genres and origins, all played at random. The sound effects, as well as the Continue theme, all come from the Genesis port of Uwol: The Quest for Money.
Game Over screen and memetic infamy
Comparison of the Game Over screen with "Unmasked".
The most notable and notorious part of the game is the shocking Game Over screen. In extreme dissonance with the overall tone of the rest of the game, the screen displays an image of Felix in a similar pose to on the title screen, except that he is tearing his own face off to reveal his skull and standing in a pool of his own blood. Like a majority of assets in this game, the picture used here is not original; in fact, it's a converted and colorized version of Kris Balerite's Felix the Cat Unmasked.
The image first came to prominence when Vinesauce's Joel streamed it, along with Super Mario World 64 and BMB's Mario Games. Joel's genuinely horrified reaction to the screen became a highlight of the stream. The screen became associated with the word "HET", after Joel's mispronunciation of the Russian word "нет" (nyet - no) as seen on the Continue screen. The screen, and the game itself, gained the nickname "Felix the HET". Numerous parodies related to other franchises were also spawned, typically containing a similarly-styled Continue screen, followed by a Game Over screen with a gory or shocking image of the main character.
The Continue theme also became associated with the theme "Puzzle Room", from the game Kirby: Planet Robobot, thanks to the YouTube channel SiIvaGunner. The channel's output is typically made up of "high-quality video game rips" that are bait-and-switches to memes, and their "Puzzle Room" upload was no different, switching to the similar-sounding Continue theme. In the video, "нет" is selected, and the "Game Over screen" is a baby with harlequin icthyosis, placed through a Hypernova filter to appear like Kirby. The video was very negatively received and has since been deleted, but has been reuploaded by other channels. Nevertheless, "Puzzle Room" became associated with Felix the Cat and HET for fans of the channel, and SiIvaGunner themselves made several self-parodies of the original video.
Level Select
Code Screen.
The level selection screen can be accessed by pausing the game, pressing the C, Up, Down and Right buttons at least 25 times each. A similar cheat code reportedly works on both Chip 'n Dale ports, as well as Darkwing Duck, but it's worth mentioning that the screen itself is exactly the same all throughout and that it says the following: "Code Screen. If you're reading this, then you're either a cheater or the greatest ever developer of this game. Now choose your round, mortal!!!", followed by the word "level" and what appears to be the current version of the game.