The artstyle contributes to half the feel of game.
If your favorite game was represented in monochrome with a bunch of stick figures I doubt it'd be your favorite game.
You could probably argue that's the situation for quite a few GameBoy games... and some of those ARE amongst people's favorites. Not to mention Tetris.
Anyways, while I can understand being put off by an out and out ugly game, they really should at least give it a try. If in playing it he can't get over it then I can't fault him, especially since that implies the rest of the game isn't enjoyable enough to make up for it.