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Level 15 - GHITGNIL
The answer to this puzzle is:
Words: HILTING, TILING, GLINT, NIHIL, THING, INTI, LING, HILI, TING, NIGH, GILT, LIN, GIT, TIL, NIL, GIN, NIT, NTH
Bonus words:
HILTING, TILING, GLINT, NIHIL, THING, INTI, LING, HILI, TING, NIGH, GILT, LIN, GIT, TIL, NIL, GIN, NIT, NTH