New Hybrid engine concept from ETH Zurich - simpler and clever

Hybrid cars are more complex and more expensive to build. Two engines and batteries and a lot of computer power are a lot to handle to save a bit of gasoline. That is at least what ETH professor Lino Guzzella thought. So he came up with something simpler. He took a small engine (approx. 750 ccm instead of 1'300 ccm) and combined it with a turbo to achieve the performance level needed. This comes with the disadvantage of delays in power delivery. To compensate for this Guzzella adds an air pressure tank where he can store air with a pressure of up to 17 bar. The pressure is built up during brake phases. And it's pushed into the turbo unit instantly in acceleration phases. The new concept is said to deliver a similar power output than a bigger engine at the gasoline consumption of a Toyota Prius. Not bad. And it comes at a fraction of the cost (approx. 20 % of a hybrid system) and I would reckon the weight is also a fraction.
A question for me remains: Is this clever engine downsizing or true hybrid technology? Be it what it is, it's a good example of intelligent engineering.