If you're of a certain age, then the name Geoff Minter and Llamasoft with bring back memories of bonkers games played on the Commodore Vic20, C64 and beyond. Full of sheep, graphics that induce LSD type trances and later, hypnotic trance music, Llamasoft games are an experience beyond just merely shooting things, you find youself zoning out and playing with your subconscious. Gridrunner Revolution is classic Llamasoft at its best and the bonus Vic20 mode unlocked after completing the first level set (all levels named after increasingly strong curries) will take you back to your misplaced youth.
If you grew up playing Playstation or Xbox games, then there will be a huge dose of WTF and this game will probably not be for you. Go search youtube for some gameplay videos if you are unsure. If you want a surreal, hypnotic blaster, then this is money well spent.