For starters, I'll be putting out this Angel Beats Review. Have fun and expect more content in the future!
Otonashi Yuzuru wakes up in the Afterlife Battlefront(it's really just a high school in the afterlife) without any memories. There, he meets Nakamura Yuri, leader of the SSS that opposes Angel in the Battlefront. Otonashi Yuzura now finds himself with an invincible body and a fight against dissappearing.
It was a great anime. It's on the same level as Clannad and possibly even greater just for having all those emotions packed into a short 13 episodes. At first it felt like I was watching Haruhi. There's a lot of comedy with Yuri resembling Haruhi a lot as well(she even has hair ribbons). Then it got deeper and I saw the emotional side of it. It has a unique plot with great art. You'll be in for a good time if you watch this anime :D
The artist for the ending song also had a song used in Clannad: Tomoyo After
Tenshi is voiced by Hanazawa Kana, a well known seiyuu for roles like Azunyan(K-on) and Kirino(Oreimo)
Key had a hand in this anime. Epic +100.