Gantz, Terra Formars Recommendations
Waifus, aliens and fight for better tomorrow. Did I mention waifus? You'll like them.
How is this NOT similar?
Bunch of people who get together for all kinds of different reasons, go through some kind of change to be able to transport to special place, where they fight evil enemy aliens. Plus some human problems like relationships, boobs, revenge...
In both cases, lot of them die (quickly AND painfully), but selected few go through some nice character development.
Both anime involve humans desperately battling against hoards of aliens resulting in many gory deaths and a continuous feeling of despair.
These two anime focus on humans trying to save the world from evil powerful aliens. The main character in both of these anime uses superhuman powers to fight against aliens with superhuman powers. Not to mention that these anime are filled with violence, blood and gore.