https://github.com/ArkEcosystem/ark-desktop - Ark Desktop Client written from scratch for ARK
https://github.com/ArkEcosystem/ark-client - ARK CLI written from scratch
https://github.com/ArkEcosystem/ark-node/commits/testnet - look at the commits and if you have some coding knowledge go through some of them and let me know if this is "code monkey" for you
Just to list some things (there is dozen more):
Removed sidechains (deprecated in favor of smartbridge)
Removed custom node version
Removed UI for stability and security reasons
Changed some constants (block rewards, blocktime etc...)
Added simple PBFT before forging new block
Ditch addresses from the protocol in favor of bitcoin like system, enabling HD Wallet as for BIP32
Completely rewritten node management using a single NodeManager and messaging system
Completely rewritten round management (removed mem_round, reward block fees to forger)
Added 64 bytes vendorField as first iteration of smart bridge
Made peers management entirely in-memory for efficiency
Strengthened the transaction management and broadcast (reject often, reject soon)
Rearchitect with relay nodes and forging nodes
Nodes broadcast only block headers.
Planned features:
Simple blockchain validation for SPV and use in lite clients
Add IPFS as first class citizen (using smartbridge addressing)
Protocol improvements (uncle forging, voting weights).
Remove unsecured API
Routing tables
Performancestable on testnet at 5tx/s
pushed to 10tx/s on devnet
update: have hit up to 25 txps on testnet