There are some good elements here, but the "glitchiness" and screen shake is overdone. The viewable area is already pretty small, limiting your time to react, along with some rather large enemies right from the start. There is just too much against the player. It also makes the text hard to read, which is problematic for new players trying to learn what your game offers. Pick the things that you most want to use and focus on them, while lessening some of the others. Maybe adding some things in later as an increasing difficulty, but right now it starts off with too much.
I also tried to use the portals to get upgrades, but was being attacked and killed while on the upgrade screen. Maybe an experienced player who know what all the upgrades are can react quickly and pick an upgrade to get out before taking too much damage from standing still, but I expected that to be a temporary safe zone while picking an option.