Jeff Keen (who died in 2012, aged 88) made whatever he fancied: paintings, drawings, sculpture, poetry, collage, animation, found footage films, live action films – sometimes a single Jeff Keen work would be a psychedelic amalgamation of all of these. Coming to prominence in 1960s Brighton, his works were entirely part of the city's DIY hippie counterculture. Experimental was the watchword.

Cartoon Theatre of Dr. Gaz is Keen's second solo exhibition at Shoreditch's Kate Macgarry – it runs in parallel to another solo London exhibition by Keen, Rayday Film, presently on display at the neighbouring Hales Gallery. The former is an example collection of the body of work that made Keen's name: from sculpture to film to prints to photography. The latter is predominantly image-based, at its centre Keen's seminal work, Rayday Film – a bright, colourful, and graphic work that's an assault to the eyes and ears – and any polite sensitivity you might have. The film, projected in the middle of the gallery, is surrounded by a series of objects – largely from the 70s – that demonstrate Keen's interest in the language of the image.

Taken together, these two exhibitions will give the contemporary viewer a very comprehensive overview of Jeff Keen the artist. From his lo-fi, handmade objects, to his epic, grand-scale films that are a shrieking litany of sound and vision. But if there's one thing to come out of it all, it's the idea that Keen was just a bit of a hippie doing things that he liked to do, and people liked him doing his things. Yes, he was a pioneering artist, but his works contain subtle criticisms of the excesses of Western culture: war, greed, commercial cultural saturation. His works hint towards society's dark side, but are ultimately shot through with the cautious (and surreal) optimism of a person who cares about such things. It's all one beautifully bonkers, multifacetedly marvellous portrait of the artist.

Jeff Keen: Cartoon Theatre of Dr. Gaz at Kate Macgarry and Jeff Keen: Rayday Film at Hales Gallery both run until 27 February.