Under the 'commands' section of the invasion templates add an option: failType.
Add another 'commands' list: failed
0 - Default. no fail conditions.
1 - if the player dies while the invasion is active, run the 'failed' commands list.
2 - if the invasion is still active when the sun rises, run the 'failed' commands list.

This way invasion developers can run a series of commands based on the player's performance. For example, repeating the invasion wave, or even resetting all the way back to the first invasion, if the player triggers the failType.