Strings attaching a character to a screen could be kinda neat [see the beginning of the video]. The sliding screen technique could be used to quickly approach or withdraw from the audience / characters with a growing or shrinking image. The flickering dissolve is achieved by wiggling fingers in front of the overhead projector.
The headlamp didn't really have enough power to make a very large image. This system is rather limited in function since the film can't progress easily. It is very portable though and can create a few interesting effects. Different lenses or mirrors used in front of the headlamp could yield fascinating results.
The use of a film loop [basically a magnifying glass] with the overhead made for a dreamy / memory style.
Happy Valentine's Day