8 bit

Recently I often saw something made in 8-bit on the Internet such like older Japanese older games.

You would use "saw" instead of "see," because it happened in the past (on April 1st, instead of today).

Since 8-bit is an art style, we say "in" 8-bit (style). Just like "in" color or "in" black and white. It talks about how something was made and what it looks like. Just a rule. English has so many rules!

We move "older" in front of "Japanese games" because "Japanese games" are very specific. You are talking about all the games made in Japan. Again, just a rule. Sorry!

Someone imitated a famous ancient art style and makes a game that remakes graphics. It was made by using the latest CG technology.

I think you have "ancient" here because you wanted to use 昔, but in English we only use "ancient" for something really really old, like the Pyramids or the Great Wall of China. You could say "a famous old art style," but I think it's fine without it.

Also, I would use "art style," since you are talking about how it looks and the graphics.

I made it into two sentences, just because it was getting long and a little confusing. It sounds better and is easier to read this way, I think.

Last thing, we always use "the latest" together. You probably learned about this in studying English, so I won't give a long explanation. But it works the same as (big/bigger/the biggest)(new/newer/the newest). If you have -est, it always has "the" together with it.

Yesterday I was excited about Google's sense of fun on April Fool's Day.

Usually in English, you are excited "about" something. Or excited "by" something. These are a little different. Here, I would use "about." Ask me if you want to know the two differences ^^

April 1st is called "April Fool's Day" since the day is about fools, I guess! (笑) To make it shorter, we call it "April Fool's"

They rewrote Google Maps like the first Dragon Quest 1st, which is an old Japanese old game, but it's the one of the most popular games in Japan.

Most of these I explained in other corrections, so I won't be boring and explain again.

This is important though, when you talk about one "game" it doesn't have an "s" at the end. Or, if you talk about a specific game like Dragon Quest. (Did you buy the newest Mario Kart game?)

If you are talking about all "games" or a group of "games" then it has an "s" on the end. You have the "s" too when you want to talk about the business of games, or make an opinion about games.

This works for everything, not just "games!" You could say "one of the most popular pandas in Japan" if you wanted to.

I've never spent my time for exploring something in Google Maps.

I corrected this above, too. Google likes to capitalize its features, like Google Search, Google Translate, etc...

Recently I often see things made in 8-bit on the Internet such like older Japanese games.

I've never spent my time for exploring something in Google Maps.