Still the idea is beautiful. Since tumors are oxygen-deficient and suppress the immune response, anaerobic bacteria would proliferate there, and wreak havoc, while in the healthy parts of the organism they would be rapidly eliminated. Additionally, since the bacteria accumulate in the tumor, and the immune system has just responded to their invasion, T-cells will flock to the tumor, destroying what remains of it in due course.

As they say, "the fame of a mathematician is measured by the number of poor papers", because pioneering works are often awkward, treading completely unknown ground. Maybe the same applies to biology sometimes?

I'm untrained in this area but it sounds like similar ideas I heard of in the last decade where injected tumor with virus (polio?) that quickly kills the tumor but then is easily cured in the rest of the body since we have solutions to them. Is this a similar situation?

Figures 2 and 3 seem to be different experiments, with n=3 and n=5, respectively. Both showed 100% survival. Obviously very small sample sizes, but still promising.

Yes in figure 2 it's 3 mice, next figure 3 they also have 5 (panel e)