I like this game. While it's really simple, it has good level design. You teach the player really methodically and I think you did a great job there. I gotta say tho - those spides shooting bullets was kind of a mistake, design wise. I wouldn't keep those bullets random because it lowers the chances of the player learning the patterns. You're doing such a good job teaching the player in this game that I feel like that randomness hurts the level design.
I have a large gripe with this game - and that is that the window doesn't focus the mouse to the application. I dunno if this is due to my browser (edge) or what. But when I press Down, the webpage scrolls downwards. I have to keep scrolling back up haha! I later read the description that you have to use the WASD.. but by then I had already played with the arrows for a long time. Either disable the inputs, or tell the player clearly in the game - never take for granted that the player will read the description. I never do!
The sound effects are REALLY loud compared to the music. It's so loud in fact, that I had to lower my audio considerably.
For a first game - I think you did an amazing job. I can see in your level design that you care about teaching the player and that's honestly really important. More important than the coding part, actually. It's a really simple game, but it's doing some stuff right. And, some other things less right. But I think that will come with practice for sure.
Keep up the great work, I hope to see you post more games on NG and grow as a dev!