Cheap/knockofish graphics. Engrish. Well balanced fun with annoyances. Bad and confusing game design.

But, most importantly, it should be made of love, from creators heart and it should show his vision and personality.  It should be a monument of honesty. 

The intentionally made "so bad it's good" games are a different and risky category.

It's kinda an art to make "so bad it's good" stuff intentionally. 

When doing so, one should have higher understanding of the cliches in the genre. If made intentionally, it's basically a commentary on the genre/culture and society. Making something lazily and without care is not a way to go.

You can also skip the intentional part and do something that could lead to so bad it's good experience.

You can treat your art as a sponge and soak it with all your internal goo. The uncontrolled by standards and conventions towel of creativity will be a great manifestation of love. Which might happen if your soul does not converge with the mainstream world.

I'm kind of on the fence about self-awareness in a "so bad it's good" game. Most non-deliberate examples don't have it, at least not on purpose. There have been some happy accidents as it were. But at the same time, if you're actually trying to make a game that's so bad it's good, you kind of have to force things a bit. You do have to go a bit meta.

To me it's really trying to balance on a knife edge. It's so easy to fall off one side or the other, ending up with either something "so bad it's terrible" or "so okay it's average". I feel much better about striking a balance with my entry this year, but I can 100% say that what I did last time didn't. It needs to be ugly, but not too ugly. It needs to be irritating, but not too irritating. Bad but not too bad. Good but not too good.

Like I said, a knife's edge.

I also feel that the gameplay needs to be legitimately good. It can be strange, and I've seen some really interesting and unusual games in that vein, but it can't be terrible. If it's frustrating, broken, or incomplete, it usually falls off into "so bad it's terrible" for me. It can appear bad but should still be good gameplay design, if that makes any sense at all.

On top of that, a lot of this is subjective and varies from person to person, and a lot of it is "know it when you see it" stuff that can't be explicitly defined. Definitely a much more challenging proposition than it would initially appear.

Philosophy aside, while I feel some entries were better fits than others, I enjoyed playing all of them and just seeing what people came up with. Even an interpretation that I don't really agree with can be interesting to look at.