The idea is interesting. If I understood correctly, if I don't to the betting board the next knight takes a really long time to come up, right?
The graphics are nice, although there seems to be something with the roof, the borders near the ceiling keep on changing colors as if the sun goes through, just a minor thing though.
The music is good but there could be some more sound effects.
Are there any differences in the weapons I sell to the knights? I didn't see any difference between selling a spear or a halberd. Also, it took a while until I managed to enable picking some weapons, it seems their trigger area is a bit odd.
Overall an interesting shop management with neat visuals.