I didn't pick up on all the things I could do (especially the power-ups were a bit vague, other than the move speed and brain ones), but I still had a lot of fun with this regardless.
The AI is sometimes infuriatingly stupid, but then just a little while later I do something very similar, so it felt kind of like playing an online game with someone you can't communicate with. Hits the theme very well, and in, I think, a clever way. I really liked the concept of the sword throwing across the invading line, rather than standing at the end of it.
Music and art were also nice; it had a sort of early console aesthetic.
Overall, a really nice and fun game. Well done!