I think there's a pretty decent concept here, but at the moment, the execution felt very rough for me, leading to a bit of a mixed bag feeling.
To start, it was very confusing for me to figure out the rules of the game: eventually I grasped that it was a bit of a defense game where you try and stop a lemmings-esque swarm from entering your portals, but until then, I had no idea. The energy bars on the portals are so tiny that I barely noticed them, and even when I did, I was confused why, when the enemy enters one of my portals, that it adds energy to their portals instead of damaging my portal, which I felt would make more sense. Furthermore, when I beat the level, I actually thought the game either bugged out or required me to manually quit out to proceed to the next level because I didn't notice the exit portal. I notice you do have little signs that point to objectives, but they disappear so fast: maybe they should stay present all the time, or at least stay for the entire duration of your first level experience to serve as a tutorial.
The combat was alright once it got going, but it was a bit annoying that you don't start with a full array of moves: instead you only get your combos piece by piece very slowly, making combat feel very boring until then. I understand that maybe it helps teach the players the moves, but it just took so long to get to the good stuff and I felt unfairly gimped. Having said that, combat still did feel somewhat lacking even with the combos since the game didn't seem to require any strategy for their use, like using heavy punches for greater knockback or to break shields over using light punches, which could maybe double as mobility options for getting around the arena faster. I'd push myself to use the combos to keep myself excited, sure, but more often than not, I'd screw myself over since it would be better and faster to just take them out with the same mash combo over and over.
Levels were a bit tricky as well, since they fluctuated in difficulty and thus, didn't feel like they gave a good feeling of progression or story to the game. This issue is a bit exacerbated by the reliance on user-created levels as well. The character also had a floaty way they moved which caused me getting caught a lot on geometry or having no way to engage with an enemy without bumping into them, causing damage and frustration.
Again, I think it is a really neat concept that could definitely work: when you have the right level with a right combination of enemies to fight strategically, it can lead to some really hectic and fun brawls where you need to improvise. But at the moment, I just wasn't get the scenario much of the time. As down as I sound on it, I still feel its a good core that I had fun with, and I look forward to the continuation of RogueBot that you allude to, which hopefully this feedback can help in some way with.