Scanning the 110 comments, I see that no one has come up with the very simple, correct answer. I'm also particularly disappointed by @yabapmatt's continued obfuscation.
Hive-engine is an ordinary application running on the Hive blockchain.
I do understand their claim that hive-engine also keeps what the hive-engine team calls a "single node blockchain". But true technical experts have called such things database logs for decades (albeit that hive-engine's is in an odd format that they claim will eventually facilitate its distribution into a being a true blockchain).
So . . . NO! Hive-engine is NOT a blockchain! It is an ordinary app running on the Hive blockchain (which does provide all the data security advantages of a blockchain -- but solely because of Hive, not because of anything to do with hive-engine).
It should also be noted that, contrary to all claims, Splinterlands is neither a blockchain nor even a proper blockchain application as it does not store all of the necessary data to replicate its current state on the Hive blockchain. Fortunately, PeakMonsters does back up the current state of everyone's collections on a regular basis -- but Splinterlands should be making absolutely no blockchain-related claims other than "we store some of our data on a blockchain . . . ".