An interesting but aged brawler.
Nekketsu Oyako is one of two games available on Japanese PSN that date all the way back to the Japanese launch of the PlayStation, the other being Crime Crackers. But whereas Crime Crackers is a difficult recommendation to non-Japanese speakers due its reliance on textual clues and menus, Nekketsu Oyako is as a simple a game as one could want. You walk right, and you pulverize everything.
This is actually a TecnoSoft joint, the same TecnoSoft that put together the masterful Thunder Force series on the Mega Drive. Those games are renowned for the amount of stuff flying around on screen at any given point with no slowdown, performing wizardry on the venerable Motorola X68000. That is lost here. Nekketsu Oyako's chunky, dollar store Final Fight designs at times overwhelm the PlayStation. Special mention has to go to a section of the second level, which takes place in a not-exactly-Biblical belly of a whale setting. A few enemies comprised of water here have some splash effects upon being battered around that bring things to an absolute crawl. It's not a pervasive issue throughout the game, but it is a real bummer when it does appear.
Meanwhile, this is fairly meat and potatoes beat'em up. Solo or with a second player, you select from three characters (with statistics cribbed shamelessly from Capcom's venerable beat'emup) and work your way through five levels of thugs and destructible junk in the environment. The most unique touch here is a sort of age system: the fatherly ersatz Mike Haggar is able to drink beer found in the environment for health, whereas the children are not. Likewise, the two playable young people are more than happy to use guns found in levels that their mustachioed father figure declines to use. It leads to a few frustrating moments, but adds a little flavor on top of the traced-over feeling.
The other distinctive elements of this game are aesthetic choices. Level designs here make the your crazier Streets of Rage levels seem positively grounded in realism. Beyond fighting inside of (and on top of) a living, swimming whale, you also get a sequence that takes place on a roller coaster that is clearly, definitely the inspiration for sections of NieR: Automata.* Levels feature a lot of unnatural pinks and greens in their palettes, and several enemies are crafted out of a biomechanical, machine fetishistic design sensibility ala Tetsuo: The Iron Man. This is paired with a soundtrack that I find myself putting on at work occasionally. It's a lot of up-temp synth rock trash, which I suppose grounds the game in a late-80s milieu that belies its origins in the mid-90s.
What really drags the game down, ultimately, are fairly mushy controls. Combat uses a recognizable special attack system if you've swam in these waters before, I never felt they did as reliable of damage as the genuine article. The usual "just move slightly up or down to avoid all attacks" pratfalls are present here as well. A very "deliberate" walking speed, even for faster characters, and some dodgy hit detection further muddy the waters.
Overall, it is best to approach Nekketsu Oyako as a fossilized PlayStation game. At times it seems like something better suited to a 16-bit console, but then you look down and see the DualShock in your hands. The general "better with a friend" cooperative play caveat applies here as well, and in fact should be the preferred way to play this title at present. Otherwise, the selling point is that Nekketsu Oyako was one of the games that was right there on shelves for the Japanese launch of the PlayStation in 1994. Come for the curiosity factor, stay for the soundtrack, and slap the difficulty down to novice.
*If Yoko Taro confirms this I will eat a hat.
-3 out of 5 members of an unusually violent family with bizarre ageist rules around who can use guns