This was neat, but I think I personally would've preferred to have both weapons on hand at all times since the hammer is required to go anywhere, so you don't really get to use the sword unless it's given to you right before somewhere important, though that's not even my biggest gripe with the sword.
As far as I could tell you couldn't fall through platforms, so if you picked up the sword at the beginning and went straight up, you get stuck. Now, admittedly you have a way to respawn yourself at the start at any time so it's not a game breaking problem, it's just... maybe a little clunky in my eyes and makes a problem that doesn't fully feel like it needs to be there. The idea of getting trapped somewhere and unable to progress (even if it's only for a moment because you can respawn yourself) because you didn't have the right tool because you simply just didn't know what was to come is a little frustrating to me personally. For me in this instance, I'd rather run back to spawn myself to pick back up the hammer, even if it might be a bit tedious, because I'm at least doing something active rather than forcing a respawn because I'm stuck and unable to do literally anything (not even explore areas as I backtrack because I overlooked them originally, a part I actually quite like in my metroidvanias) simply because I decided to try out the sword. It honestly makes me not really want to use the sword because I don't know where else I'll get stuck if I do, and anything the sword can do the hammer can as well so I may as well keep the hammer, so I have zero reason to pick up the tool that has the major downside of "I risk getting stuck if I'm not given a hammer back later".
Anyway though, the hammer is very satisfying to use, so I'm happy about that. And despite my gripes with the sword, I did enjoy my time with this game. Music felt grand and a bit adventurous, which gave me a sense to go exploring the world to see what I could find and do to escape this colosseum. The skull boss was a bit much, but the Great Statue was a good bit of fun, so it evened out in the end. Everything felt fluid and nice, save for your slow walking speed, which I think may as well just get boosted up into your run speed as I was running around the whole time anyways since I don't know why I would wanna walk over run here. All in all, this was fairly solid and fun. Great work on making this and I hope my feedback isn't too harsh.