DISCLAIMER This post reflects my personal opinion only; it does not constitute investment advice of any kind.
To me it looks like a project that aims at writing a better implementation of blockchain software, using concepts from software engineering, distributed systems and programming language theory, to write node code that's more scalable, more performant and more precise.
It is a platform on which all sorts of DApps can be built.
They have created a special strongly-typed language called Rholang to write smart contracts in.
Among other things, this enables using the compiler to help you write contracts that can be formally verified to be correct.
Tokens: RHOC, REV
RHOC is the current token for RChain platform apps.
REV will be a staking token once the mainnet is launched (RHOC tokens will be swapped on a 1:1 basis for REV tokens).
Phlogiston (yeah) is the name given to gas-like units of operation in smart contracts.
Phlogiston is not a Token, it's a way of measuring how much work is done by transactions and smart contracts.
It's built in Java
Uses proof of stake for verifying transactions
There can be multiple "namespaces" in the blockchain so that transactions don't necessarily need to be broadcast globally.