Hollup, you gotta turn on Turbo Mode (shift clicking the green flag) first, bud (or turbowarp here: https://turbowarp.org/1235777107?turbo&interpolate). Move your mouse to move the nova. Hold WASD or the arrow keys to shoot. Dodge the light novas (they're red uhh) and shoot them to get gems. Collect multiple gems in a row to get more points. And SURVIVE!
I was bored, so I recreated Neopets's "Nova Defender" from scratch (heh, get it?? Scratch???) while purely using Scratch's (scratch get it???) assets. Mostly shared this to test on Turbowarp, but I've commented a few scripts inside, so you're free to look inside. So this project isn't done, and expect weird stuff. Also, sorry if the music's a little weird. Any small amount of lag can cause it to desync, so I tried having different parts of the song resync so it happens less. Still happens though. So I think Turbowarp may be able to fix that. Edit: Raising the framerate within Turbowarp helps to sync up the music, but in turn, it makes everything else, like the enemies, faster. I'll work with interpolation for now.