It seems like the release of the Game Boy, an incredibly popular system that was also significantly lower-powered than most of its contemporaries, was seen as something of a challenge to some developers. Games like X and Faceball 2000 sought to do things that conventional wisdom would tell you were impossible on there. And they were pretty successful, technically at least. Whether these achievements resulted in something that was actually practical or enjoyable to play is a little less clear.
Bionic Battler (also known as Vs. Battler) isn't quite as ambitious as the games listed above, but it is still a game that's attempting to do more than you might expect a Game Boy game to do. It's a first person deathmatch game, though it can't quite stretch as far as the incremental movement of Faceball 2000. Instead, it's got dungeon crawler-style blob movement: the map is a grid, every character always occupies exactly one square on the grid, you can only face the four cardinal directions, and you always move one space at a time.
So you're in the maze (the layouts of which are either selected or generated at random when the stage starts), and you and a couple of CPU partners have to hunt down your opponents, who are trying to do the same to you. You've got two weapons at your disposal: a punch that obviously only works at point blank range, and a missile that can be fired in a straight line ahead of you, but takes a few seconds to charge. Annoyingly, though, to win, you have defeat every member of your opponent's team, while they only have to defeat you. If it was too difficult to have you take control of a teammate upon defeat, they could have alternatively had a similar "captain" on the other team who needed to be defeated for an immediate win.
There are five difficulty levels to pick from, though there's no progression of any kind, and as far as I can tell, no way to complete the game. You just pick a level, and then either win or lose at it. I assume this means the game was actually designed with versus play in mind, which, considering that I've never seen anyone play an original Game Boy game via link cable that wasn't Pokemon, seems like an Ozymandian display of hubris. The one thing you do get when you win a match is a little cutscene where your pilot disembarks from his robot, goes into the next room, and shakes hands with a general, who gives him a laughably small amount of prize money (though there's no item shop or anything in which to spend this money).
Bionic Battler, unless you cajole someone into playing it against you, isn't much more than a temporarily amusing display of technical achivement. I guess that if it was one of only a few cartridges you owned as a kid in the actual early nineties, you'd probably get a lot of play out of it, and you wouldn't have a bad time doing so, either. But in the year 2024, you're going to play it for a few minutes, and then probably never think about it ever again.