This feels like one of the more weirder entries (at least to my point of view - take it how you will), First the positives:
1) The game on its own, is actually pretty fun! As a bullet-hell player myself, it's.. not really a bullet hell (as how you describe it on discord haha) - but it does have some elements of having to dodge bullets and the lava on the ground. Despite the weird random nature that can occasionally be infuriating - there were also moments where I can go, "hold on, theres a weird pattern" and I could exploit that to get to the gems.
2) Great overall game feel - this is something I'm still learning to achieve and I think you did it justice here! For example, I personally like your sound integrations into hit, gem pick up, etc and the appropriate sound effect for them. Did you make those sound effects too - may I know which program? Very well done!
3) The controls feel very smooth, responsive - a crucial element to a high-stakes game such as this.
The reason as to why I think this is also a weird entry is:
1) I don't think you needed the time rewind mechanic to complete the game. Because the time rewind mechanic seems to introduce a few inconsistencies, and also detracts from the supposed charm of the game, while rewinding - the turrets stop firing bullets, and bullets that were gone - do not rewind from the point of destruction, so essentially rewinding time becomes a "grace period". Maybe that was your intentional game design - so I wont press further.
But I meant that from a game design perspective - I felt like your game is quite complete without a time rewind mechanic.
Regardless though - great game! I played through medium mode and it was very much challenging, and also very fun to beat! A pleasant sight from start to finish and if you expand on the game - I'll be on the lookout!
Cheerios!