You should just go back and play the games yourself. It won't take long and you'll be 100x more hyped for the game afterwards. Plus...they're some of the best games ever made.
You have 2 options. You can play them as they came out or in chronological order.
As they came out: Metroid II/Super Metroid/Metroid Fusion/Zero Mission (Remake of Original Metroid)
Chronological Order: Zero Mission (Remake of Original Metroid)/Metroid II: Return of Samus/Super Metroid/Metroid Fusion
As it stands, Metroid: Other M is going to take place between Super Metroid and Metroid Fusion. However, it is going to tie into pretty much all the games I mentioned above. You'll enjoy it a lot more if you go back and play all the games.
Six upcoming games you should look into:
