mbl

Going off your list I would agree with others with my top recommendation being Kara No Shoujo.
The Infinity series and Critical Point are some other options, mainly going off all the sci-fi.
If Clannad is what you are considering "realistic" then you could try all the other Key games, Kana Little Sister, Family Project, Kirakira (Kirari's route as others said), or Da Capo. 

Cho Dengeki Stryker = Kid wishes to become a superhero and has a comic book hero's mind transferred into his body.
Tears To Tiara = The protag has cults worshiping him at the start as the bringer of the apocalypse, if that gives you an idea.
Rance = Rance is the greatest badass in eroge
Wanko To Kurasou = Ex-prostitute protag managing a moe-blob harem. 
Heartwork = Boy finds gun, boy becomes spy
Policenauts = Written by Kiojima

You don't need to take a course to learn how to hack, you just need to have developed a proper CS mindset. Proper hacking requires programming and assembly code reading, but beyond that, unless you are hacking a novel using a common engine (Which would likely have an extraction tool available anyways), each process you are trying to hack is it's own puzzle which you won't have a guide for solving. As I said before, I believe learning VN hacking is for people who have a well defined interest in CS; if you properly program in your spare time or are in middle of getting a CS degree, then reverse engineering might be a helpful thing to practice alongside programming.
 
This is the only real VN specific tutorial I found for the reverse engineering side of hacking. It goes over the basics of reverse engineering VNs, but it is a real pain to read and contrary to what the writer claims assumes a lot of prior knowledge. I would suggest taking it slow and trying googling anything he references that leaves you confused (especially reading ASM code, as his intro will leave someone with no prior ASM knowledge lost). 
http://proger.i-forge.net/Stage_Once_-_a_Visual_Novel_hacking_tutorial/IPD

Oral sex is a plus

For those of you who don't know anything about the Mother series, it's a series of quirky and fun RPG games that originated from Japan since the NES-era. They are quite very popular over there and here too.
 
There are three games that have officially been made, but Mother 2 was the only American release (which was called Earthbound) and the protagonists of Mother 2 and 3 can be found in the "Super Smash Brothers" games as Ness and Lucas.
 
Mother 3 never officially came out in America but the fanbase was strong enough to support its popularity and there has also been a fan-made translation that looks superior than what would have normally been the official translation--if there were one.
 
The Mother games were directed by Shigesato Itoi. He claimed a few years ago that Mother 3 would be the last one in the series. During an interview, he stated that he would not mind if fans were to make a fourth game, and so a group of people decided to give it a shot.
 
 
 
Now on to the main topic; Mother 4 is in production and has been for a few years now. The interesting fact about this game is that it's being made by Mother fans, and they try to keep it true to the primitive games by keeping similar aspects (especially the music).
 
The new trailer was previewed a few weeks ago and so far, it does look very promising:
 

 
If you haven't tried any of the Mother games, I suggest you start with Earthbound or Mother 3~

https://www.youtube.com/watch?v=zeQ6NGskkak

Yeah, that seems pretty applicable.

It depends on what you are looking for, there are a lot of different ways you can go with this vague of a starting point. Whether you were interested in romance, or adventure, or gameplay ect. would change my suggestion. There are a lot more games that use this trope in many genres (for both protag and heroines), I suggested two fantasy VNs because that seemed to me most likely what you were looking for since you mentioned "Game worlds". 
 
If fantasy is what you are looking for, then Kiohime Musou if you're interested in a war story based off the romance of three kingdoms or Duel Savior if you are looking for more standard fantasy adventuring.
 
 
 
It's fine. Standard animu fantasy plot and character with pretty good gameplay. Wouldn't top my list anywhere, apart for maybe this thread, as I was never too into Eien no Aselia.

https://www.youtube.com/watch?v=txE4jFlgu60

*Looks at Nosebleed's post count* It would appear Nosebleed is almost 3x cooler than you. 

http://www.appjenny.com/Android/App/siy.sukutore
 
Here you should get the App (Sukutore)... But don't use the Google play link because obviously the app isn't there anymore... Have fun.

Tool's Lateralus is probably the only album from my youth that I still listen to on a somewhat consistent basis today. The song Lateralus is one of my favorite songs of all time, easily on my top five. It's one of those things that I think I will never get sick of for my entire life. After who knows how many hundreds of times listening to it over the years, every single time I listen to it again, it feels as invigorating and amazing as the first time. Basically, it's a masterpiece. 

Seriously, why? How do you even come in here and first post on the forums is to revive a long-dead thread.
 
I was about to start writing up the proper list of gameplay-driven VNs that this thread never got and make some comments about how weird people's definitions of "gameplay" were until I saw how old this thread was. 

One of my all time favorites
 

The bit in Kira Kira is more of an understandable depression and not at all violent.
 
 
Makes the thread title of "protag gone nuts" kinda interesting. Heartwork still fits perfectly, protag accidentally swaps bags with an assassin. Bloodlust drives him to do some crazy stuff. Summaries will talk about him turning into an assassin himself, but that is just one of the routes. 

Anything will play the game, and since that is the only reason you brought up for buying it I don't have many specifics for suggestions.
Anyone who uses both android and IOS, as I do, will tell you Android > IOS. If they're in your price range, tablets with proper windows on them would be best (Though I don't know if this game you're wanting is available on windows).
 
The main reason you would have for getting more expensive tablet models is higher res/more power. If you're wanting higher to play 3d games or demanding applications you'll need a more expensive tablet. If you'll be wanting to watch higher-res videos on the tablet, then you'll need to shell out for a high res tablet. Otherwise, if all you are wanting to do with the tablet is play games like this one, surf the web, ect. then there isn't much reason why you shouldn't buy a cheap android tablet in whatever size you are wanting
 
.I own a Galaxy Note 10.1 and the main reason you'd have for getting it over cheaper models is the fact that it has a pen digitizer, which lets you do some low-res doodling with pressure support. 

https://www.youtube.com/watch?v=wGXO8sF3ISk

Damn seriously man...i cant sop listenin to that song..its all ur fault lel~~~~
 

http://www.siliconera.com/2015/02/20/so-erm-theres-a-nicolas-cage-dating-sim-now/

guys, there's this thing called google...
 
it will continue to exist after fuwanovel stops hosting torrents.

I think I'm at the point where I can watch the whole trailer in my head just by listening to this now. 
 
https://www.youtube.com/watch?v=Wovefinmh0Y