The solution was hidden in three different ways:

• Counting the numbers of chain links between the balloons to get THREEPARTSAREHIDDENANDTHISISPARTA EOPBWLH.
• Interpreting states of balloons (inflated / deflated / burst) as Morse code to get PARTB NFREADE.
• Interpreting colors of balloons as Morse code to get PARTC DSENECN.

Writing the parts underneath:

EOPBWLH
NFREADE
DSENECN

one can read END OF SPREBENWAELDCHEN.