It's hard not to judge an engine by the games made with it... To me that's like not judging a racecar by how fast it goes, sure there is other criteria but that's the meat.
It is better to evaluate the engine yourself for the project you are planning to do with the requirements it has (not making the entire project, of course, but if you - say - want to create a huge detailed world you can procedurally place entities in the world and see how the engine copes with that and if it provides tools to address any issues).
but if you see a similar game already made, then you can clearly claim that it's possible in the engine. Saves time and effort.
Really? What's the killer app for Dark Basic? I've never hated an environment more than that one. I would be shocked if anyone could put up with it long enough to make something good.