Some quick thoughts.
1. Lots of movement options, There seemed to be a double jump/ground pound, and a slide in there.
2. Leveling up per weapon? That could be interesting, and it puts value on weapons you find earlier vs. what you find later.
3. The abilities shown looked a bit disapointing, everything except the gun buff was like, "here's my magic grenade"
4. Enemies looked good, moved well seemed fun to fight.
5. Disapointing visual feedback, I'm sad they went the route of hitmarkers and life bars instead of more fluid feedback like the shield flare in halo.
6. Need to invest "Talent points" in guns, how limited will talent points be, do I need to make decisions, or can I just blindly upgrade.
7. PLayer count went to 7 during the group event, previously 6 players max was hinted