Nice first release, I quite liked all the girls and their personalities.
The setting/premise seems mainly inspired by Fate/Grand Order. That said... "there are issues being caused in the past that cause issues in the present, and we fix the former to stop the latter" is a workable plot, if you treat it as no more than an excuse/frame for the events. But for those who enjoy worldbuilding - such as myself - I would like this to be much more fleshed out. What do the villains gain by causing such issues? How do they cause them, exactly? What is the nature of a time rift? How is one resolved? I'd like to see all those things explored/explained, alongside some more general ones involving time travel: what if you kill someone while on the past? What if you have sex with someone? And such.
That is more of a wish of mine, but when it comes to the most pressing need of the game, or it's main issue really... it's that it's pretty evident that you are not a native English speaker. Now, the text isn't broken, per se, but a trained eye can see you using turn of phrases that just aren't employed in English (to me it resembles the way Japanese works). I would try and get a native English speaker to do an editing pass of the text for you, if at all possible, while you keep improving your English proficiency. That said, I much prefer the text as it currently is, than for it to be edited by a machine program, as I've seen other devs do. This is not a criticial issue that makes the game unplayable, so please don't resort to that.
Again, this was a good first release. Keep doing what you are doing, keep improving, and hopefully the next release comes soon, I am looking forward to it ^^