I read that it was your first game, so congrats on pulling this out :)
The critical step to improve is to fix game breaking bugs. Like whenever I grow or shrink, I can no longer shoot, which is annoying. As well, one enemy got stuck between me and my cannon, so I couldn't do anything basically. And enemies can spawn in the wall and get stuck.
One thing that I didn't understand: It seems that the ammo is limited somehow? And differentiated between the two guns? You need an UI to show this.
Otherwise, the basis is nice. There are good ideas, which need to be refined and improved.
Why would I use one ray vs the other? What type of situation do I need to adapt to, to make each option interesting and to create interesting choices for the player?
Maybe different enemies spawn in the arena, or there are various arenas with different layouts...
Anyway, good job :) Keep working on this, and keep improving!