im naturally atracted to swordfighting games so I gave this a try. and I liked it
it feels natural to move the sword with the mouse like that, and since this is a duel fight with the view locked at the enemy you don't have the typical problem of the genre (my own swordfighting game included) of needing the mouse for something else (rotating the view)
I found two flaws:
- attacking doesn't quite work as you described it. the instructions say 'swipe the mouse with the left mouse button held'. this would mean I need to click and hold, then drag. but that didn't quite feel like it because just by moving one pixel counts as a drag, and this sensitivity makes it impossible to get the attack the way I intend it to.
it felt more effective to move the mouse first, and mid-movement just click the mouse button
- you can spam attacks indiscriminately, and the game becomes extremely easy
was it fun? yes, it's a fresh take on swordfighting
how challenging was it? not that much after the first try. the collision detection is way too broad and generic (ie. at any angle will your sword block the enemy's) so it's really easy to turtle. not so easy to hit him, sure, but if you keep parrying eventually you get there (or if you spam attacks). I also felt we both had too much health points, but maybe that's just my own taste of a more 'life or death' scenario in swordfights.
now you mention this is a game mechanic, so this tells me this is only a small part of your game. if you have the time to improve it and add variety I'd say it's worth it.
btw it works in win8, but MS smartscreen filter didn't like the installer at all