@MetallicK2MK Well Sega were known for rushing games. Guessing that this had a very short deadline, I think Sega was pushing this one to be done by Christmas but was just a bit late in Japan (December 28). Don't know when it came out in the US, Brazil and Europe, the latter may be early 1992.

It was done by S-Plan who also ported Woody Pop (needs hacking for the missing levels), Frogger (prototype later leaked out, cancelled due to copyright issues between Sega and Konami) and may have started on Aerial Assault, completely different to the Sanritsu Master System game around this time. According to this post on SMS Power, S-Plan had access to the Master System version source code. It ended up being cutdown and had to be released on a smaller ROM size since Sega wanted to save money on making the cartridges, similar to what happened with Enduro Racer (outside of Japan) and Captain Silver (US). That would explain the missing stages.

It's more of a reskin of the master system version, with missing stages and unfinished graphics. It's particularly noticeable on the back of Squil2's head, where you can see where the new graphics were supposed to fit in when put in a 8x8 grid (there are even floating pixels on the sides, supposed to be tips for the horns) or the Tomos enemy where only a single frame was changed. The game's brightness is also lower, just in case anyone wonders if there was a mistake.
I wonder if this game was supposed to be something more at one point.

Despite the name, it's an all unique game in the series. The enemy designs are wild as hell