Hello everyone, nice to welcome you on our site, this page even has Level 4 answers. I enjoy it =D
Level 4 - IPMHRUT
The answer to this puzzle is:
Words: MIRTH, THRUM, THRIP, PRIM, RUMP, PURI, RUTH, PITH, PTUI, THRU, UMP, PIU, IMP, PIT, TIP, HUT, PHI, HIM, HUM, RUT
Bonus words:
MIRTH, THRUM, THRIP, PRIM, RUMP, PURI, RUTH, PITH, PTUI, THRU, UMP, PIU, IMP, PIT, TIP, HUT, PHI, HIM, HUM, RUT