and if you didn't save before a dialouge choice pops up then you have to redo the entire scenario to get back to the choice
Not really, you can save game at any moment during battle, just not when dialogue is on. So before killing the boss, try saving in case there's a choice.
For the one who asked about swordman upgrade, i found one on the very first mission when you have to run away.
Just send your main character running to the exit after you burn the arrows, and the other one (Robert) send him to loot the 4 chests on south room. Eventually the princess will catch up with Robert (but you should be able to get all 4 before it), then you can simply exit with your main character and win the scenario since it doesn't matter if characters "die" in battle. If you do it the other way (main character looting and robert trying to exit, and you get caught, you'll get a game over scene).
I wouldn't compare it to succubus senki, as this was made as a side project of ToT. And yes of course, it lacks polishing, refining, and could be improved a lot, like adding a simple gallery mode or someplace to watch the scenes you got on your run, but be realistic, which one you want to see being worked on, this one or ToT? Me, I wouldn't ask anything else from this game, it was nice, fun, i enjoyed it, but I'd rather see them back to work in ToT and leave this one as it is.
And for those who wonder where to find something, don't worry, you can advance chapter without harm, then go back by exitting through stairs or doors on one of the new side quests (they usually have a circle on them).