whats the diference between this and the normal koikatsu game and does it require the other game aswell in order to be able t oo play this ?
The difference is that:
1. NPCs cannot start interactions with you, like conversations, in the same way.
2. There are new mechanics to conversations in the form of topics.
3. The graphics are roughly the same, but the default shadowing is improved a bit.
4. You're not in a school.
You do not need both to play, you only need this to play this, they are separate games entirely.
I have two questions. Is there cheat option to gather conversation topics? I have activated (multiple times and have multiple lovers) lover visit at evening event but nobody appears, is this like pure random thing?
There is no such cheat, at best you can get more to appear in one time period, making you able to collect more of them in one time period before having to advance time to get more.
Visits are a bit random, but they are based on a chance system with higher H bar levels being a higher chance. At no point are you guaranteed a visit unless you have a specific bonus that says as much from the harbor shrine. Also, any girl you have already done an H scene with that day will not visit, automatic 0% chance.