England trail New Zealand 2-1, but have made three successive totals over 300 for the first time, including a record 408-9 in the opening win at Edgbaston.
"It has been really enjoyable," said Hales. "It looks like we've won our fanbase back in one-day cricket."
"There are fresh faces and a lot of young talent. Guys are expressing and enjoying themselves in the field."
England meet the Black Caps in the fourth match of the series at Trent Bridge on Wednesday.
Despite 88 off 47 balls from skipper Eoin Morgan England lost a rain-affected second match at The Oval by 13 runs on Friday and were then beaten by three wickets at Southampton on Sunday, even though Morgan recorded a third successive half century.
Aside from Morgan, four other batsmen have made fifties, while Joe Root and Jos Buttler struck centuries at Edgbaston
Bowlers Steven Finn and Adil Rashid have returned to international cricket with five wickets each and Northants' David Willey took 3-69 at Southampton in only his second ODI.
"We're pretty inexperienced," said Hales. "We've pretty much matched the Kiwis so far and played some really good cricket, so in terms of how inexperienced we are and how raw we are, I think we've done pretty well."
Hales, who made his one-day international debut in August last year, has now played 13 matches and scored his maiden half-century in the defeat at The Oval.
"It is nice to get a consistent run. In the past I've been in and out of the team and never really got a proper go at it," said the 26-year-old.
Somerset's 21-year-old twins Craig and Jamie Overton have been added to the squad for the final two matches to replace injured pace bowlers Chris Jordan and Liam Plunkett.
The one-day series ends in Durham on Saturday, and after a Twenty20 international on Tuesday, England begin the Ashes Test series with Australia in Cardiff on 8 July.