There are some main platform differences, as many have pointed out, but those who like one of the other generally fit into one of these two reasons:
1) Botting/AI vs Human Interaction only - When people started writing bots to play MySQLGame, others seemed to get furious. If you want to do well in the Schemaverse, you likely have to write some form of AI at some point, either in SQL or any other platform you wish.
2) Story vs no Story - People who like MySQLgame really appreciate the fact that the story is simply the numbers. I think that does make for a pretty unique game on its own, even outside of the SQL aspect of things. The Schemaverse is a space battle.
Shameless plug, if SQL games interest you and you will be at DEFCON 21 in Las Vegas this year, there will be another Schemaverse championship. Start getting ready now and it will take up very little of your conference time but you could win some great prizes and sweet sweet SQL game street-cred. https://forum.defcon.org/forumdisplay.php?f=690 for more information
As for adding awesomeness, I would say the core devs do a pretty fantastic job of that. I just utilize it is odd ways ;)
Check out: https://schemaverse.com/
See you at DEFCON 21!
Why do you need "SQL injections" if you are writing direct SQL statements in the first place?
The Schemaverse has a SQL Injection trophy with no actual code path to win it. After 2 1/2 years, there are two people who have it.