As of Rift 1.0.2-28, when pressing "Singleplayer" to view the list of worlds, the game crashes. If you have nothing in your saves folder, it will instead crash when you select Create World and proceed to generate the world. This is the crash report https://gist.github.com/raphydaphy/fb18edee6d6fe06cf335543b2f6c6d05

This issue is present in every release of rift from v1.0.2-3 to v1.0.2-28 and happens no matter what mods you install, including with none installed.

The root of the problem seems to be that resourcePacks is not added to the refmap.

This can be "fixed" by adding this:

"resourcePacks": "Lnet/minecraft/server/MinecraftServer;ad",

under this:

"org/dimdev/rift/mixin/hook/MixinMinecraftServer": {

in mixins.rift.refmap.json in the .jar file.

Edit: Here's a crude guide to get it to work with MultiMC: https://gist.github.com/gbui/61fae5e035608935510c5c347989b499