This achievement is not hard, its very time consuming..
There are 8 different game types which you need to get 25% in each. So lets get started.
You need to play a match with 43 different roster fighters(UFC/PRIDE). The quickest way to do this would be make a Created Fighter with 0 stats in 2 weight divisions. Select a roster fighter and fight against the Created fighter. Run across the octagon(LS) and spam strong punches(Y X and hold towards with the left stick). Once you win, choose select fighter. Pick a new fighter and rinse and repeat.
(To access your created fighter click the left stick to the right twice)
2) Title Mode
This mode will take up the majority of your time. You are required to play 6-8 matches(if you win all of them) with 43 different roster characters. This means it would take you 258 matches at the very least, but it will probably be more like 300+. I would recommend starting the the heavyweight division and use the fighters with the best standing stikes.(UFC AND PRIDE) Use the same method you used for Exhibition. Each match will take about 1-3 minutes game time. When youre done with the good heavyweight fighters, drop down a weight division then repeat the process.
They're are a total of 205 challenges, meaning you have to unlock 51 of them to obtain 25%. MY advice would be to use Jon Jones. He has an overall ranking of 95 with good striking and a takedown from the clinch. You can view the challenges by clicking title defense mode then pressing X. I completed 62 challenges by making it to the 26th fight. That was without looking at the challenges as well.
There are 6 different options for tournaments, meaning you only need to do 2 of them. The quickest way to do these would be to set up a UFC Tournament.
Pick the weight division with your CAF that is rated 0. Set up the tournament with these settings
Weight : Whatever weight your CAF is in.
Difficulty : Beginner
Tournament Size : 4
Mirror Match : ON
The others dont matter.
Next step, select the best fighter in the weight division your in for one slot. Then for the other 3 slots select the 0 CAF.
Go to the bracket with the best fighter and press A. Select him. Play the match and use the same method for Exhibition. After you win that fight go to the other bracket and dont select a side and press A. Then put it to simulation and go.
Play the final match and thats one down. Then do the exact same thing for the pride tournament. Done, lets move on.
5) Ultimate Fights Mode
In my opinion the easiest 3 for this mode are..
Quinton Jackson vs Wanderlei Sivla - BOTH SIDES.
This will unlock the "History is Best Both Ways" Achievement
Mauricio Shogun vs Quinton Jackson - Shogun Side.
I found these 3 the easiest.
6) Career Mode
This is assuming you dont care/already have the other career achievements. Start career mode, select a roster fighter. It doesnt matter who. You dont need to play any matches. Pass the tutorials in the beginning then when you're given the option to choose fight do so. After that, select FIGHT NOW. Then simulate your fight. Once you're given the option to choose your next fight, then do the exact same thing. Do this 48 more times and you will complete career mode. You must do this in 2 DIFFERENT weight divisions. So do the exact same thing if need be.
7) Event Mode
This is fairly quick and easy. Go to event mode and click Load Event. Hit the RB and you are given 10 "Historical Events" Choose one of these and put it on beginner. You only need to play in the main event of the event you can skip the other fights. You must do this 3 times.
Click on tutorial --> Guided Tutorial. You must complete 17 of these. This will only take 10-15 minutes since you will be doing the very basics of the game.
After that, you're done.
Like I said at the beginning of the guide, this is very somewhat time consuming but its mostly because of Title Mode.
Best of luck to those working for this one. If there is a negative vote, please leave a comment or message me so I can touch up the solution.
Have a good day!