Game as a shoot'em up works pretty good. It doesn't maybe have some awesome graphics but gameplay itself is solid. I like background sound used for the game and the intro sequence (you didn't need to voice act it, yet you did, so respects for that). Shooting sound could be a bit more varied to not seem so repetitive, but that's something really minor and more like QOL stuff.
I would probably have some words about balance and technicality. So first - it feels like main, time reverse mechanic regenerates way too slow for the second stage, where enemies are mostly bullet sponges and which have bullets with big explosion range - I think either they could be less hp heavy or the player would have quicker regeneration there, at least for that stage (I saw that there was some kind of upgrade for the ship, but I really didn't found occassion to take it and not die). I also had a werid glitch, where I technically completed the boss but did get main menu button instead of continue and I had to beat him up again in order to actually play on new area. Lastly, if game will ever grow, I recommend adding something like level selection or saving system, so the player won't need to complete every stage again since they died at the last one.
Overall, you made a great game!