The game as a whole would be better in renpy. Renpy is superior for this game type than what he chose. Devs that use other offbeat engines that don't allow gallery/scene viewers, cheats, etc as easily perplex me. Stuff like that should be in a game from day one imo. Don't get me started on having to have an entire group of people who make "mods" to put things in games that should already be in every game from day one.
And I fail to see why "cheating" in a game is a negative. Games are for fun and enjoyment, not some rule following ego trip.
Engines are a personal opinion. Just because one easier to code with than another doesn't make it unanimously superior. Silver is comfortable with what he's using at the moment.
Can you imagine the outcry if he were change engines AGAIN just because YOU want him to? I'm sure he doesn't come here at all so why bother. You want to tell him to use Ren'Py, you have to tell him yourself. The game runs perfectly well on its current system. I don't see the need for him to use something else.
The Offline version should have no lag and if the grind is what's upsetting you then this game is not for you.
Nor is it suitable for a gameplay binge.
As you said, games are fun and enjoyment - that much we can agree on. For me, challenge is part of the fun.
When I was MUCH MUCH younger, I'd cheat my way through tough spots in games. I don't do that now. Unfortunately, a lot of games use grind to artificially pad out the game and extend the overall playtime. Personally, I find this is not the best way of padding things out.
[Off Topic Here]
Hypothetically speaking, let's say for example you want to implement an underwear-only rule. This game would have you jump through hoops and do enough slutting about so Kate would even consider it. By that time she's spent a lot of time naked on her back.
Small dialogue changes and maybe minor pose changes would help to tell the player they're on the right track at least.
Yes, I admit this game does drag a bit at times and a new engine may help but as I said, another engine change might kill it outright. He lost a lot of patrons when he switched engines the last time because it took the new programmer a long time to catch up to where Silver needed him to be.
You want it on Ren'Py? Either do it yourself or find someone who can.