This game was fun, and gives flash game era vibes, but it was also boring. Pretty soon I became an unstoppable amalgamation of nodes that could annihilate anything in my path within mere seconds. It took a long time for the polygons to catch up(in terms of strength), and when they did, I couldn't improve because the nodes were so scarce. 

Maybe the score could be calculated by how much time you've been alive, or maybe a wave system?

The screen was also cluttered with the nodes I had collected, so it was hard to see the enemies coming. I also think the node types are too diverse, there's so many different types, and some of them are basically useless(ex: swordsman, normal node, defense). The power-ups are also over-powered.

Maybe if I could move the nodes around, it would encourage strategy? Maybe also add a radar/minimap, or arrows pointing to nodes/polygons? Maybe also add a "Shop", were I can sell/buy nodes/upgrades? Maybe upgrades could also be scattered around the world? What if some projectiles reloaded/went faster than others? What if the polygons actively seeked out the nodes to destroy them?

Wow, this is the longest review I have ever written. I hope I'm not being rude, and that this review helps. :)