This game has a beautiful opening title scene but missing options. You only have one option and that's for the sound, which is all controlled in one setting. It's pretty standard in RPG Maker games to be able to separate BGM and SFX levels.
I liked the particle stars floating in the background, the silhouette of a spider, the flashing and pulsing title "Berry" was very clearly the center focus. Nice song choice and great start, well done.
Good job showing the spider walking sprite even while it's behind an obstruction. I like the method you've chose here.
The scene transitions are really cool and I like the puzzle/platform/timing tasks. Usually I don't like this sort of stuff, but the controls feel good in this game and it makes it more fun. I found the controls to be just a bit tighter on WASD over controller, so for most of the game I use Controller, but for the boss fights I have to use WASD to beat them.
All the artwork is very well done and I very much like the style.
It took me about five tries to beat every boss, mostly due to trial and error and having to learn the moves. It felt challenging but fair, with a minor exception that the purple fireball on the giant beetle had a hitbox that was too much larger for it's animation.
I was certain that the golden slug would be the last boss as I've been playing for well over an hour now, but nope... The game just keeps going. It's a little too much for a game jam entry, but it goes to show that this project has what it take to become a commercial game. Very well done, and I wouldn't automatically assume this was RPG Maker, but there are some dead giveaways that a trained eye would spot.
Overall, this is a fantastic entry into the game jam. Very well polished with tons of interesting mechanics. Not my favorite style of game, but for what it's trying to do, it does it very well. Great work and keep it up!