Instead of no rally points like on cea, make rally points. Also:
Let’s say there is a mission called cortana. Here is how achievements would go. Normally, 40G. Here:
To reach RPA: 10G Breaking through
To reach RPB: 10G Reunion Tour
To reach end: 20G Wake me, when you need me
This will give the player a feeling of lots of levels, rather than only 9-10.
My achievement ideas other than levels:
5G Well you kinda suck: Campaign easy
125G The one and only: Campaign normal
150G Guest appearance: Campaign heroic
200G Galaxy renowned: Campaign legendary
50G Universally recognised: Campaign legendary alone
1G +1: Unlock every achievement
343G Specially selected: Feature on any of:
Waypoint
Fails of the weak
HaloWaypoint (YouTube)
Gamefails