Quick answer
The two documented badges track major progression milestones
Rebirth! is awarded for rebirthing for the first time. Rebirth resets progression, so do not treat the badge as a reason to reset immediately. Read the rebirth guide, verify the current panel requirements, and understand the reset warning first.
Complete Index is awarded for unlocking all of the ASMRS. A Jul 30 recording showed 56 slots, but that is a dated snapshot rather than a permanent promise. Track the live Index and use the Complete Index route to organize missing entries.
The remaining badges are named A, S, M, R and !. Their public Roblox records supplied no descriptions at the review date. The letters may look suggestive, but assigning requirements without evidence would mislead players, so this page leaves them unresolved.