Hmmm, I just felt kinda confused by this one. Maybe it's my fault for playing it as a single player, but the option was there, so keep that in mind.
While it seems like a decent 2D platformer in some respects, I just felt like the game was very repetitive and generic, lacking an intriguing core concept or satisfying feel to it all. It felt like once you've played it for a few minutes you've seen everything as it just keeps recycling the same enemies over and over and not introducing any new obstacles or mechanics. Aspects that could've been interesting, like the AI partner which you can somewhat guide, or the different world's gravity, or the upgrade system, lack focus and just feel token, not adding anything but just stuck on as if just by having them it'd make this plain game somehow seem better than it is. Eventually it gets some stuff like boss fights but for me that was too little too late as I had already quit from boredom.
The most interesting aspect of the game I encountered was when I died and I was left with only my AI partner, who I could still somewhat guide despite being dead by signaling him to move forward, but he would automate his jumps and attacks. This was a rather unique control scheme that could be interesting and reminded me of games like Gyromite, but it really felt like it wasn't intentional and the way to play. The AI was largely unreliable anyway, regularly getting stuck on things or falling into pits.
The controls felt terrible, in particular with the way jumps kept you moving forward with momentum despite no longer holding the forward button, which would usually kill your momentum in other platformers, made it very awkward and feeling like you're constantly sliding on ice. Combine this with the way enemies can just rush in quickly from the right and smash into you and you've got a real frustrating loop of damage that feels unavoidable.
To add to the pile further, I really disliked the unnecessary scanline filter, which only served to hurt my eyes.
I dunno, maybe there's something interesting in here that could be salvaged, but right now it just feels like an unfocused mish-mash with bad AI, bad jumping controls, and at its core just a rather bland and uninspired side-scroller. Again, maybe if you focused on that unique aspect of helping to guide an AI through the battle, it might be a unique experience at least? Might've been a case where you needed to 'follow the fun', but maybe that's just me.