Well, I've had a read through of what you've done so far and I can say, first of all, the art is not at all bad for early in a webcomic. Check out practically any webcomic and you'll find the art usually starts off pretty bad, but gets better over time. You've alreday started off well, so keep at it and you'll only get better.
The spelling and grammar does have some issues, but not to the point of being unintelligible. If you have access to a word processor (something like Open Office, if you need a free option), you might benefit from writing your script in there to check for errors, and always proof read your work before publishing, of course. The only other things I would suggest as far as the text goes is that you could probably afford to make the font size smaller, and it would probably look a bit neater to use the same font for most text. There's a lot of changes between fonts as it is, so I recommend picking one and sticking to it for standard dialogue. Obviously sound effects or situations where someone's voice may be distorted are exceptions to that. Oh, and with the positioning of word balloons, do try to arrange them in a way that will naturally guide the reader through the right order. It's not easy, I know, and even pros mess that up sometimes. But if you're unsure, just look over what you've done and ask yourself if the correct reading order would visually make sense to someone else.
Now, as far as the story goes, I probably wouldn't have introduced so many characters at once if it were me, because we don't really get enough time with any of them yet to really grok who they are and what they're about. But I do appreciate that may well be a storytelling choice and we're supposed to learn about the characters and setting gradually over time (I mean, let's face it, that worked for Game of Thrones). If so, that's totally valid. Massive lore dumps before we get to the action can be very tedious, after all (I'm looking at you Dark Crystal: Age of Resistance).
And talking of the setting, I do appreciate the inclusion of Westopolis and GUN in the second chapter, as that helps ground things in Sonic's world. But before you continue with that, do consider changing Venus's rank. Sergeant Major is actually a very low rank in the military. It's a non-commissioned rank, so below an officer's rank. If you want to imply that Venus is a high ranking officer, which I get the impression you do, I'd recommend Colonel at the very least. Probably something higher, like a General, honestly.
Don't worry, though. I made the same mistake with my own comic when I got started. I made a character who was a Corporal and basically second-in-command of GUN, and Corporal is actually a lower rank than Sergeant Major.
If it helps, officer's ranks (at least in the US Army and Air Force) go:
Second Lieutenant
First Lieutenant
Captain
Major
Lieutenant Colonel
Colonel
Brigadier General
Major General
Lieutenant General
General
I've no immediate military experience myself, so I had to research a lot of this to get it right. And that's good advice for anything you want to include in a work of fiction where you don't have any direct experience. Do a little research and that way you can at least make it seem as if you know what you're talking about.