Clean installation with Forge 1.7.10-10.13.4.1558 (recommended) and ReplayMod-1.7.10-2.5.1-jar
fml-client-latest.log

No issues found with ReplayMod-1.7.10-2.5.0-jar

Grrrr, probably ForgeGradle again. The 2.5.1 jar is missing random files again (note how it's only 2.5MB whereas the 2.5.0 one is 10.5MB).

I have rebuilt 1.7.10-2.5.1 locally and replaced the broken download. I have not tried to run the new jar (merely checked that it now has the expected size) but given 2.5.0 works, 2.5.1 will probably work as well.

Verified