It is a good plugin, anyway i found 2 bugs accidentally, normal user i believe won't do this.
Using example.nsi that provided in SpiderBanner_plugin.zip, here are the errors:
1. inserting "SpiderBanner::Show /NOUNLOAD $R0 $R1" again between "SpiderBanner::Show /NOUNLOAD $R0 $R1" and "SpiderBanner:
estroy" will close installer immediately
2. click and hold banner, until get MUI's finish page, release mouse, and could not click anything, until press CTRL+ALT+DEL and click cancel.
Hopefully could strengten your plugin.