How is this different from Bitcoin?

Litecoin is a peer to peer cryptocurrency. By peer to peer or p2p we mean, data or asset(s) are shared or exchanged between 2 parties without involving any central authority. This P2P takes a decentralized approach for interaction between individuals and groups.
Litecoin is an open-source software, released under MIT/X11 license, (a permissive free software with very limited restrictions on reuse and therefore has a high compatibility). One can say, Litecoin was an early bitcoin work-around or altcoin, created in October 2011, by Charlie Lee, who was working with Google at that time and he is now an Engineer Director at Coinbase.
Litecoin was created as a source code of Bitcoin client with a decreased block generation time (which is 2.5 minutes) with increased number of coins. Litecoin, rather than using SHA -256, it is using Scrypt (pronounced as ess-crypt) algorithm(scrypt is a password based key derivative function and this algorithm was specifically designed to make it costlier for large-scale custom hardware attacks as it needs a large amount of memory, however, for legitimate user, authentication function needed to be performed once so the overall time required is negligible).
In 2013, Litecoin showed massive growth in value with 100% jump in 24 hrs, doubling its value. In 2017, Litecoin adopted SegWit which is also called “segregated Witness”, which is a soft fork change in the transaction format of Bitcoin. In this mechanism, the transaction it is split into two segments, removing the unlocking signature (“witness” data) from the original portion and added as a separate structure at the end. The original section still contains the sender and receiver data/ information, and the new “witness” segment added would contain scripts and signatures. The original data segment would be counted normally whereas the “witness” segment would be counted as 1/4th of its original size, thus, decreasing the time required for transaction to be verified, validated, executed and completed.
In May 2017, Litecoin completed its first lightening network transaction ( a “layer 2” payment protocol designed to operate on top of a blockchain-based cryptocurrency, for making micro payments of cryptocurrency through a network of bidirectional payment channels without delegating custody of funds) and transferred 0.00000001 LTC from Zurich to San Francisco in under a second.
As Litecoin is using The Scrypt algorithm, therefore, making ASIC and FPGA devices for mining complicated and expensive to produce.